DOCSLIB.ORG

A Tunnel Diode Reflection Amplifier for RFID Antennas

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Tunnel Diode Reflection Amplifier for RFID Antennas A Tunnel Diode Reflection Amplifier for RFID Antennas F. Amato, G. Durgin School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta, Georgia 30332–0250 [email protected], [email protected] Abstract—Long range back-scatter RFID systems have in- energy level below the potential barrier, it can still be found creased the importance of a high signal-to-noise ratio received behind the barrier. In a highly doped p-n junction, there are at the reader. The signal-to-noise ratio is directly related to the energy levels in the valence band of the p-type material at the reflection of the loads used on the tag which is traditionally same energy as some levels in the conduction band of the n- limited between -1 (short) and 1 (open). By using a tunnel diode type material separated by a thin potential barrier [2]. From biased in the negative resistance region, it is possible for the tag the quantum mechanics theory, there is a finite probability that to amplify (Γ > 1) the back scattered signal. The paper illustrates this idea, explains how the tunnel diode has to be implemented, an electron can be found beyond the potential barrier; such and compares the theory to early results. probability increases as the barrier becomes thinner. Further requirement is that there should be unoccupied levels on the I. INTRODUCTION side to which the particle will tunnel. There are two main areas where the tunnel diodes found Applying a forward voltage to the junction causes a flow usage: switching circuits and sinusoidal applications for neg- of electrons from the n-type side to the p-type side causing ative resistance amplifiers. In a reflection-type amplifier a an increase of the tunneling current followed by a current propagating signal incident on the negative resistance region of decrease; although the tunneling effect will end at a certain the tunnel diode (Fig. 2) is reflected with increased amplitude point, the p-n junction current will keep flowing and it will [1]. Such application is of high interest in RFID semi-passive increase with the applied voltage. A negative resistance region antennas as it would allow to increase signal-to-noise ratio (Fig. 2) makes the tunnel diode interesting to be used as a received at the reader. single port amplifier [1]. Back-scatter systems use a reader that transmits a contin- First part of the work consisted in studying the behavior uous wave (CW) signal to the tag which receives the CW of some tunnel diodes provided by Aeroflex/Metelics (Model signal. The CW signal enters through the tag antenna and MBD5057-E28) and comparing them with the expected results switches between two loads to modulate data into the CW and theory. To measure the Direct Current curve shown in Fig. waveform which is reflected back out of the tag antenna. 2, the tunnel diode, in series with a 1 Ω resistor, has been The modulated signal then propagates back through the air connected to a DC power supply; a multimeter has been used to the reader where the signal is demodulated and processed to measure the current across the circuit and a voltmeter has by a computer. Traditionally, a short and an open are used as been used to monitor the voltage across the resistor in order to the two loads in order to keep them as far apart as possible be able to compute the exact voltage acting on the tunnel diode. from each other to maximize signal-to-noise ratio for positive Fig. 3 shows the schematics of the experimental setup used to resistance loads. If the negative resistance of a tunnel diode is test the tunnel diode. For each 0.02 V step of the DC power used for back-scatter technology, the signal-to-noise ratio can supply the current in the multimeter and the voltage at the be dramatically improved at the expense of more consumed port of the resistor have been saved and the data subsequently power to bias the tunnel diode (Fig. 1). processed to find the voltage across the tunnel diode; Fig. 2 shows the results of the DC curve. The negative resistance region is between 56 mV and 280 mV which is where the tunnel diode must be biased to behave as a negative resistor. The currents ranged from 561 µA to 129 µA. The slope shown in Fig. 2 is the inverse of the resistance which is calculated in Eq. 1. The resistance is -518, but this is only valid over the region from 56 to 280 mV as previously stated. The negative resistance of the tunnel diode is: 0:28 − 0:056 = −518Ω (1) Fig. 1. General back-scatter system with tunnel diode 129 · 10−6 − 561 · 10−6 II. THEORY III. EXPERIMENT A tunnel diode works using the quantum mechanical phe- The aim of the work is to demonstrate the feasibility of a nomenon of tunneling: although an electron (or a hole) have reflection type amplification using a tunnel diode. A reflection- Fig. 5. Schematic of the designed reflection amplifier Fig. 2. DC curve of a real tunnel diode purpose, an appropriate amplifier circuit has been designed and realized to be used at the center frequency f0. Fig. 5 shows the schematic of the circuit in which the inductance L has been used to allow to bias the tunnel diode at the required voltage. The experiment consisted in connecting port 1 of the circulator with a signal generator providing a source of -10 dBm at f0 = 4.1 GHz, port 2 with the amplifier connected to the biased tunnel diode and port 3 with a spectrum analyzer to measure the output signal. If port 2 is terminated in a negative resistance and a signal wave enters port 1, all the energy emerges at port 2, is reflected and amplified by the negative resistance, re-enters port 2 and emerges at port 3. The gain of the amplifier will be the square of magnitude of the reflection coefficient at port 2 [1]. Fig. 3. Circuit used to draw the DC curve of the tunnel diode G = jΓj2 (3) type amplifier can be implemented by connecting a signal The performed experiment measured the input and the generator and the tunnel diode to a circulator in order to be able output power from the amplifying circuit at f0 = 4.1 GHz; to observe the amplified signal incident on a spectrum analyzer the tunnel diode has been biased at a DC voltage (0.18 also connected to the circulator [3]. The setup is shown in Fig. V) that puts it in the negative resistive region. The power 4. A circulator isolates the reflection amplifier from both the from the signal generator is reflected back to the spectrum generator and the spectrum analyzer; the reflection amplifier analyzer and the received signal level has been observed. A terminates the transmission line of characteristic resistance R0 DC block at the spectrum analyzer port has been used to in a negative resistance jRj, giving a reflection coefficient avoid DC current to leak across the amplifying circuit. Early which is negative and greater then 1. results showed an amplification of the input signal of 3.6 dB at the working frequency while biasing the tunnel diode in − jRj − R the negative resistance region; no amplification effects where Γ = 0 (2) − jRj + R0 observed while biasing the tunnel diode at a voltage outside the negative resistance region (above 0.2 V). To use a tunnel diode as a reflection amplifier the following Through these first experiments, it has been possible to criteria need to be met: biasing the diode in the negative demonstrate the possibility of using a tunnel diode to amplify resistance region of the DC curve and have a transmission line back-scattered signals of semi-active RFID tags. Further stud- with a negative resistance at the center frequency f0. For this ies and investigations will follow with the aim of integrating a tunnel diode reflection amplifier in a RFID experimental tag antenna. ACKNOWLEDGMENT This work has been possible thanks to the support of the US-Italy Fulbright Commission. REFERENCES [1] J. O. Scalan, Analysis and Synthesis of Tunnel Diode Circuits, John Wiley & Sons Ltd., 1966. [2] R. F. Pierret, Semiconductor Device Fundamentals, Addison Wesley, 1996 [3] M.K. McPhun, U.H.F. tunnel-diode amplifier, Electronics Letters, 1969. Fig. 4. Experimental setup.
Load more

Recommended publications
  • A Noise Investigation of Tunnel-Diode Microwave Amplifiers* A
    1961 PROCEEDINGS OF THE IRE 739 A Noise Investigation of Tunnel-Diode Microwave Amplifiers* A. YARIVt, MEMBER, IRE, AND J. S. COOKt, MEMBER, IRE Summary-An analysis and derivation of the noise figure of a must consider the shot noise accompaniying the tunniel- tunnel-diode microwave amplifier are presented. The agreement be- ing process.7 There are two separate and independenit tween the measured noise figure and the theoretical results is an in- direct check on the existence of full shot noise in germanium tunnel tunineling currents, one consisting of electrons tunnelinlg diodes at microwave frequencies. The limiting noise temperature of from the N to the P side of the junction, which we de- the amplifier is elIR/2k, and can be approached by using diodes with inote by ii, and a second curreit, i2, made up of electrons small (RC) products in which the extreme overcoupling (load mis- crossing the junctioni in the opposite directioni. The niet match) and high gain can be achieved simultaneously. measurable dc current is Io-= ii -| i2 . Since the cur- INTRODUCTION renits ii and i2 are uncorrelated, the total shot noisel is represented by a current generator of mean-square A MPLIFIERS utilizing tunniel diodes were first re- amplitude, ported by Chang' at frequencies up to 80 Mc. He also suggested that the noise conitribution of the diode was due to the shot noise accompanying the j2 = 2e( 1iI + i2 I )B, (1) tunneling process. This suggestion was con1firmed by Lee and MAIonitgomery,2 who showed by measurements where e is the electronic charge and B is the bandwidth at 5 Mc that full shot noise was inideed genierated by the in cycles per seconid in which the noise is conisidered.
    [Show full text]
  • Px4v; All 4.Us/ ATTORNEYS Nov
    Nov. 16, 1971 J. E. CONANT ET All 3,619,912 WSUA SIMULATION DISPLAY SYSTEM Filed Aug. 9, 1968 4. Sheets-Sheet I. 12 O MODEL&r 3 MOON TRANSA ORY Motion systEM F.G. 25 D SPLAY SYSTEM GENERA Puy RPOS OG A ARCRAFT COMPER SMUAYOR 5 INVENTORS yOAN. E. CONAN & ATER F.B.CZEK px4v; All 4.us/ ATTORNEYS Nov. 16, 1971 J. E. CONANT ETAL 3,619,912 WISUAL SIMULATION DISPLAY SYSTEM Nov. 16, 1971 J. E. conANT ETAL 3,619,912 WISUAL SIMULATION DISPLAY SYSTEM ATTC)RNIEYS Nov. 16, 1971 J. E. CONANT ET All 3,619,912 WISUAL SIMULATION DISPLAY SYSTEM 3,619,912 United States Patent Office Patented Nov. 16, 1971 2 3,619,912 ual techniques, for coordination of the several monitors VISUAL SIMULATION DISPLAY SYSTEM in an overall display in which an image target is trans John E. Conant, Arlington, and Walter F. Buczek, Spring lated in a path across the several monitors, in any direc field, Va., assignors to Melpar, Inc., Falls Church, Va. tion thereacross, to correspond to the path of such an Filed Aug. 9, 1968, Ser. No. 751,522 image in actual flight of the craft as simulated by the con Int, CI. B64g 7/00, G09b 9/08 trols exercised by the trainee. U.S. C. 35-12 5 Claims Each monitor is supplied with delayed sync pulses and blanking information from its own video control network, with control coordination effected, in a preferred embodi ABSTRACT OF THE DISCLOSURE 10 ment, by computer input signals developed in response An optical image display is provided in a mosaic of to trainee control.
    [Show full text]
  • Two Terminal Special Purpose Devices First Year
    www.uptunotes.com Content: - Special Purpose two terminal Devices: Light-Emitting Diodes, Varactor (Varicap)Diodes, Tunnel Diodes, Liquid-Crystal Displays. 1- Light Emitting Diode (LED) Light Emitting Diode is a photo electronic device which converts electrical energy to light energy. It is heavily doped P-N junction diode which under forward biased emits spontaneous radiation. The diode is covered with a transparent cover so that the emitted light may come out. Construction- In an LED, the upper layer of p-type semiconductor is deposited by diffusion on n-type layer of semiconductor. The metalized contacts are provided for applying the forward bias to the P-N junction diode from battery B through resistance R which controls the brightness of light emitted. Fig: LED construction Working of LED The LED works on the principle of electroluminescence. When a P-N junction is forward biases, the electrons in N- region cross the junction & recombines with holes in P-region. When electrons recombine with the holes, they move from conduction band to valence band which is at lower energy level. While moving, the additional energy is released by the free electrons which appear in the form of light due to the special material used in the LED. The energy released depends on the forbidden gap energy which determines the wavelength & the colour of the emitted light. Materials of LED The materials which are the mixtures of Gallium, Arsenic & Phosphorus are used in LED to obtain different coliour of light. S.No. Material Symbol Colour 1 Gallium Arsenide GaAs Infrared(Invisible) 2 Gallium Phosphide GaP Red or Green 3 Gallium Arsenide Phosphide GaAsP Red or Yellow By: Navneet Pal Email:[email protected] Page 1 www.uptunotes.com Output Characteristics- The amount of power output translated into light is directly propotional to the forward current If , more forward current If , the greater the output light.
    [Show full text]
  • Basic Electronics Engineering. Chapter-1
    Basic Electronics Engineering. Chapter-1 1. Diode Circuit 1.1 Define Electronics & its application. The world's reliance on electronics is so great that commentators claim people live in an "electronic age." People are surrounded by electronics—televisions, radios, computers, mobiles, Laptop and DVD players, along with products with major electric components, such as microwave ovens, refrigerators, and other kitchen appliances, automatic vehicles, Robotics, as well as hearing aids and medical instruments and numerous applications in industry. Definition: The branch of engineering which deals with current conduction through a Vacuum or Gas or Semiconductor is known as Electronics. An electronic device is that in which current flows through a vacuum or gas or semiconductor. This control of electrons is accomplished by devices that resist, carry, select, steer, switch, store, manipulate, and exploit the electron. Or Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies. Commonly, electronic devices contain circuitry consisting primarily or exclusively of active semiconductors supplemented with passive elements; such a circuit is described as an electronic circuit. Pre Knowledge (Some of the basic definitions): Passive Components: Capable of operating without an external power source. Typical passive components are resistors, capacitors, inductors. Active components: Requiring a source of power
    [Show full text]
  • Pioneering Study on Tunnel Diodes Study on Static Induction Transistors (SIT)
    C-8 Pioneering Study on Tunnel Diodes Leo Esaki (1925－) started the study of PN junction diodes as a chief scientist in the diode research laboratory at Tokyo Communication Industry Co., Ltd., (currently Sony). After trial and error for about one year, he discovered the fact that when making the width of the PN junction of germanium as thin as 10 nm, negative resistance—the higher the voltage, the lower the current, contrary to conventional knowledge—occurred because its current-voltage properties were dominated by the impact of tunnel effects. This discovery was the first example of verifying the tunnel effect of quantum mechanics in the diode and the birth of new electronic devices—tunnel diode (or Esaki diode)—in electronic engineering as well. Then in 1973, L. Esaki was awarded the Nobel Prize for Physics together with Ivar Giaever who made the achievement of tunnel effects in ultrahigh conductors. Initially, the tunnel diode was made from germanium, however, now it is also made from gallium arsenide and silicon. It has also been used for various electronic circuits, e.g., oscillation circuits, amplifying circuits, frequency converters, and detector circuits. C-9 Study on Static Induction Transistors (SIT) In 1950, Junichi Nishizawa (1926－) developed the static induction transistor (hereinafter, SIT) applying the perfect crystal growth technique and high purity crystal growth technique originated by himself. He introduced a transistor having a rising property into the field of conventional transistors, where the properties of both the bipolar transistor and the field-effect transistor (FET) were limited to only the property of current saturation to increase in voltage.
    [Show full text]
  • Tunnel-Diode Microwave Amplifiers
    Tunnel diodes provide a means of low-noise microwave amplification, with the amplifiers using the negative resistance of the tunnel diode to a.chieve amplification by reflection. Th e tunnel diode and its assumed equivalent circuit are discussed. The concept of negative-resistance reflection amplifiers is discussed from the standpoints of stability, gain, and noise performance. Two amplifi,er configurations are shown. of which the circulator-coupled type 1'S carried further into a design fo/' a C-band amplifier. The result 1'S an amph'fier at 6000 mc/s with a 5.S-db noise figure over 380 mc/s. An X-band amplifier is also reported. C. T. Munsterman Tunnel-Diode Microwave Am.plifiers ecent advances in tunnel-diode fabrication where the gain of the ith stage is denoted by G i techniques have made the tunnel diode a and its noise figure by F i. This equation shows that Rpractical, low-noise, microwave amplifier. Small stages without gain (G < 1) contribute greatly to size, low power requirements, and reliability make the overall system noise figure, especially if they these devices attractive for missile application, es­ are not preceded by some source of gain. If a pecially since receiver sensitivity is significantly low-noise-amplification device can be located near improved, with resulting increased homing time. the source of the signal, the contribution from the Work undertaken at APL over the past year has successive stages can be minimized by making G] resulted in the unique design techniques and hard­ sufficiently large, and the overall noise figure is ware discussed in this paper.-Y.· then that of the amplifier Fl.
    [Show full text]
  • A Spice Behavioral Model of Tunnel Diode: Simulation and Application
    International Journal of Control and Automation Vol. 9, No. 4 (2016), pp. 39-50 http://dx.doi.org/10.14257/ijca.2016.9.4.05 A Spice Behavioral Model of Tunnel Diode: Simulation and Application Messaadi Lotfi1 and Dibi Zohir1 1Department of Electronics, Advanced Electronic Laboratory (LEA), Batna University, Avenue Mohamed El-hadi Boukhlouf, 05000, Batna, Algeria [email protected],[email protected] Abstract This paper provides an Analog Behavioral Model (ABM) in Pspice of a tunnel diode The Pspice parameters are implemented as separate parameterized blocks constructed from Spice (ABM) controlled sources and extracted through experiment. A tunnel diode based oscillator is also proposed and simulated using circuit analysis software. The behavior of the tunnel diode is simulated and compared to the measured data to show the accuracy of the Pspice model. Close agreement was obtained between the simulation and experimental results. Keywords: Tunnel diode, tunnel diode oscillator (TDO), Spice simulation, resonant tunneling diode (RTD), Analog Behavioral Modeling (ABM) 1. Introduction Leo Esaki invented a tunnel diode, which is also known as “Esaki diode” on behalf of its inventor. It’s a high conductivity two terminal P-N junction diode doped heavily about 1000 times greater than a conventional junction diode. Because of heavy doping depletion layer width is reduced to an extremely small value of 1/10000 m. When a DC voltage is applied in the forward bias operation, a TD I-V curve features a region of negative differential resistance. At low voltages (< 0.5 V in Figure 1) electrons from the conduction band of the n-side will tunnel to the hole states of the valence band of the p- side through the narrow p - n junction, creating a forward bias tunnel current.
    [Show full text]
  • This Is an Open Access Document Downloaded from ORCA, Cardiff University's Institutional Repository
    This is an Open Access document downloaded from ORCA, Cardiff University's institutional repository: http://orca.cf.ac.uk/112084/ This is the author’s version of a work that was submitted to / accepted for publication. Citation for final published version: Han, Yu, Li, Qiang and Lau, Kei May 2017. Tristate memory cells using double-peaked fin-array III-V tunnel diodes monolithically grown on (001) silicon substrates. IEEE Transactions on Electron Devices 64 (10) , pp. 4078-4083. 10.1109/TED.2017.2738675 file Publishers page: http://dx.doi.org/10.1109/TED.2017.2738675 <http://dx.doi.org/10.1109/TED.2017.2738675> Please note: Changes made as a result of publishing processes such as copy-editing, formatting and page numbers may not be reflected in this version. For the definitive version of this publication, please refer to the published source. You are advised to consult the publisher’s version if you wish to cite this paper. This version is being made available in accordance with publisher policies. See http://orca.cf.ac.uk/policies.html for usage policies. Copyright and moral rights for publications made available in ORCA are retained by the copyright holders. > REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < 1 Tri-state memory cells using double-peaked fin- array III-V tunnel diodes monolithically grown on (001) silicon substrates Yu Han, Qiang Li, member, IEEE, and Kei May Lau, Fellow, IEEE quality III-V buffers within a few tens of nanometers has been Abstract— We demonstrate functional tri-state memory cells demonstrated [15]-[22].
    [Show full text]
  • Basics and Types of Diodes
    Basics and Types of Diodes Introduction to Diode: A diode is an electric device that permits the flow of current only in one direction and restricts the flow in the opposite direction. The most ordinary sort of diode in current circuit design is the semi-conductor diode, even though additional diode technologies are present. The word “diode” is traditionally aloof for tiny signal appliances, I ≤ 1 A. When a diode is positioned in a simple battery lamp circuit, then the diode will either permit or stop flow of current through the lamp, all this depend on the polarization of the volts applied. There are various sorts of diode but their fundamental role is identical. The most ordinary kind of diode is silicon diode; it is placed in a glass cylinder. The symbol of diode is represented as follows: Diode Operation: A diode starts its operations when a voltage signal applies across its terminals. A DC volt is applied so that diode starts its operation in a circuit and this is known as Biasing. Diode is similar to a switch which is one way, hence it can be either in conduction more or non-conduction mode. “ON” mode of the diode, is attained by forward biasing, which simply means that higher or positive potential is applied on the anode and on the cathode, negative or lower potential is applied of a diode. Whereas the “OFF” mode of the diode is attained with the aid of reverse biasing which simply means that higher or positive potential is applied on the cathode and on the anode, negative or lower potential is applied of a diode.
    [Show full text]
  • UNIT-I: Special Diodes- LED, Varactor Diode, Photo Diode, Schottky Diode, Tunnel Diode; Their Characteristics and Applications. Transistors As a Switch
    UNIT-I: Special Diodes- LED, Varactor diode, Photo diode, Schottky diode, Tunnel diode; their characteristics and applications. Transistors as a switch. Applications of PN Junctions: BJT (Bipolar Junction Transistor) P HBT (Heterojunction Bipolar Transistor) Rectifiers N Zener Diode Junction Diode Varactor Diode J U Switching Diode Tunnel Diode N C PN Junction Diode Solar Cell T Photo-Diode I Photo Detector O Light Emitting diode & Laser Diode N JFET FET (Field Effect Transistor) MOSFET - memory MESFET - HEMT Common Applications of Diodes: Rectifier Zener LED Schematic symbol Bias for normal Switched back and Reverse Forward operation forth between forward and reverse. Si: V = 0.7 V V = 0.7 V (not 1.2VV 4.3V Normal VF F F F normally operated) Ge: VF = 0.3 V Equal to applied Equal to V . Equal to applied Normal VR Z voltage. voltage. Primary factors to I0 and VRRM ratings. PD(max) and VZ ratings. VF(min), IF(max), and VBR consider for device substitution Types of Diodes and Their Uses PN Junction Diodes: Are used to allow current to flow in one direction while blocking current flow in the opposite direction. The PN junction diode is the typical diode that has been used in the previous circuits. A K P n Schematic Symbol for a Representative PN Junction Diode Structure for a PN Junction Diode Zener Diodes: Are specifically designed to operate under reverse breakdown conditions. These diodes have a very accurate and specific reverse breakdown voltage. A K Schematic Symbol for a Zener Diode Types of Diodes and Their Uses Schottky Diodes: These diodes are designed to have a very fast switching time which makes them a great diode for digital circuit A K applications.
    [Show full text]
  • 90 Nm 32 32 Bit Tunneling SRAM Memory Array with 0.5 Ns Write
    2432 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS—I: REGULAR PAPERS, VOL. 58, NO. 10, OCTOBER 2011 90 nm 32 32 bit Tunneling SRAM Memory Array With 0.5 ns Write Access Time, 1 ns Read Access Time and 0.5 V Operation Anisha Ramesh, Student Member, IEEE, Si-Young Park, and Paul R. Berger, Fellow, IEEE Abstract—Functional robustness is one of the primary chal- a unique negative differential resistance (NDR) characteristic. lenges for embedded memories as voltage levels are scaled below 1 NDR circuits generally operate below 0.5 V which is a key goal V. A low-power high-speed tunneling SRAM (TSRAM) memory to reduce power consumption. Power consumption is generally array including sense amplifiers and pre-charge circuit blocks op- erating at 0.5 V is designed and simulated using available MOSIS related to the square of the voltage. The folded I-V characteris- CMOS 90 nm product design kit coupled with VerilogA models tics of an NDR device pair creates a simple latch that when used developed from this group’s Si/SiGe resonant interband tunnel in conjunction with transistors enables novel circuit configura- diode experimental data. 1 T and 3 T- 2 tunnel diode memory cell tions for logic, mixed signal and compact low-power embedded configurations were evaluated. The memory array assigns 0.5 V memory [1]–[6]. as a logic “1” and 0 V as a logic “0”. Dual supply voltages of 1 and 0.5 V and dual threshold voltage design are used to ensure high Ultra-low power operation is the dominant issue for em- sensing speed concurrently with low operating and standby power.
    [Show full text]
  • Investigations of Tunneling for Field Effect Transistors
    Investigations of Tunneling for Field Effect Transistors by Peter Matheu A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Applied Science & Technology in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Tsu-Jae King Liu, Chair Professor Sayeef Salahuddin, Member AS&T Professor Chenming Hu, Outside Member Spring 2012 Investigations of Tunneling for Field Effect Transistors Copyright 2012 by Peter Matheu 1 Abstract Investigations of Tunneling for Field Effect Transistors by Peter Matheu Doctor of Philosophy in Applied Science & Technology University of California, Berkeley Professor Tsu-Jae King Liu, Chair Over 40 years of scaling dimensions for new and continuing product cycles has introduced new challenges for transistor design. As the end of the technology roadmap for semiconduc- tors approaches, new device structures are being investigated as possible replacements for traditional metal-oxide-semiconductor field effect transistors (MOSFETs). Band-to-band tunneling (BTBT) in semiconductors, often viewed as an adverse effect of short channel lengths in MOSFETs, has been discussed as a promising current injection mechanism to allow for reduced operating voltage for beyond MOSFET technology. This dissertation discusses the proposal of BTBT for tunneling field effect transistors (TFETs). Some early work is briefly reviewed to better appreciate the academic re- search landscape regarding BTBT. Then, experimental observations of a steeply switching enhanced-Schottky-barrier MOSFET are analysed in detail and the steep characteristic is plausibly explained by metal impurity trap states near the source tunneling junction. Next, follow-up experiments to investigate the role of traps in BTBT are reviewed with a likely explanation that traps in close proximity to the tunneling junction can lower the activation energy for BTBT.
    [Show full text]