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Wide-Bandgap Semiconductors in Space: Appreciating the Benefits but Understanding the Risks

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Wide-Bandgap Semiconductors in Space: Appreciating the Benefits but Understanding the Risks https://ntrs.nasa.gov/search.jsp?R=20200003156 2020-06-17T23:19:15+00:00Z National Aeronautics and Space Administration Wide-Bandgap Semiconductors in Space: Appreciating the Benefits but Understanding the Risks Jean-Marie Lauenstein NASA GSFC, Greenbelt, MD, USA To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 1 Acronyms and Abbreviations Acronym Definition Acronym Definition Acronym Definition • 2-D Two Dimensional ID Drain Current SBD Schottky Barrier Diode AlGaN/AlN Aluminum Gallium Nitride/Aluminum Nitride IDSS Drain-Source Leakage Current SBIR Small Business Innovative Research BVDSS Drain-Source Breakdown Voltage IG Gate Current SEB/GR Single-Event Burnout/Gate Rupture C Carbon IGSS Gate-Source Leakage Current SEE Single-Event Effect DDD Displacement Damage Dose InP Indium Phosphide Si Silicon EC Conduction Band Energy IR Reverse Current SiC Silicon Carbide Sn Tin EF Fermi Level Energy ISS International Space Station JBS Junction Barrier Schottky diode SOA State Of the Art; Safe Operating Area Egap Bandgap Energy STMD Space Technology Mission Directorate ESA European Space Agency JFET Junction Field Effect Transistor LEO Low Earth Orbit SWAP Size, Weight, And Power EV Valance Band Energy TAMU Texas A&M University cyclotron facility FIT Failures In Time LET Linear Energy Transfer TID Total Ionizing Dose FOM Figure of Merit MESFET Metal-Semiconductor Field Effect Transistor Metal Oxide Semiconductor Field Effect UWBG Ultra-Wide Bandgap FY Fiscal Year MOSFET Transistor VDMOS Vertical Double-diffused MOSFET GaAs Gallium Arsenide NO Nitric Oxide VDS Drain-Source Voltage GaN Gallium Nitride PIGS Post-Irradiation Gate Stress VGS Gate-Source Voltage Ga2O3 Gallium Oxide R&D Research and Development VR Reverse-bias Voltage GCR Galactic Cosmic Ray RDS_ON On-State Drain-Source Resistance VTH Gate Threshold Voltage GEO Geostationary Earth Orbit RF Radio Frequency WBG Wide Bandgap HEMT High Electron Mobility Transistor RHA Radiation Hardness Assurance Xe Xenon RHBP Radiation Hardened By Process To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 2 Outline • • Overview – Bandgaps: the simple explanation – Wide-bandgap (WBG) technology advantages & applications Overview 0 < – Space environment hazards ct) <ro • Radiation Hardness Assurance (RHA) of Commercially- ~ Mature WBG Semiconductors Sn-doped Ga2O3 wafer WBG RHA (ac) ) I – SiC discrete power devices – GaN high electron mobility transistors (HEMTs): • RF The Future •Enhancement-mode • A Glimpse into the WBG Semiconductor Horizon – Qualification standardization & technology maturation Reprinted with permission from Yao, et al., JVSTB, vol. 35, p. 03D113. Copyright 2017, – The future of SiC and GaN American Vacuum Society – Ultra-Wide Bandgap (UWBG) semiconductors • Diamond • Ga2O3 To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 3 Overview 0 Wide-Bandgap Technology Overview: < CD <ro What’s a Bandgap? (Simply Speaking) :E • Conduction Band Egap Valence Energy(E) [eV] Band • As atoms come together to form a crystal, their electron shells form bands: – the highest-energy band containing electrons at 0 K = Valence Band – the next highest energy band = Conduction Band • Electrons in the conduction band (and subsequent holes in the valence band) are able to move freely about the lattice and thus conduct current • In order to become conducting, an electron must have enough energy to jump the gap – this jump can be assisted by traps, or energy states, located in the band gap Wide bandgap materials have different electrical properties than conventional bandgap materials (e.g., Si) due to their different band structure and band gap To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 4 Wide-Bandgap Technology Overview: Properties Associated with the Bandgap Overview 7 • 0 < ct) ~ Conventional 6 <ro 6 - [::=J WBG ~ ~ Ultra-WBG 5.5 >5 - 4.8 ......Cl) >- 4 ElCl) - C: w 3.3 3.4 Q.n, 3 - C) "O C: n, 2 - co 1.4 1.12 1 - 0 I I I I I I I Si GaAs 4H-SiC GaN J3-Ga2O3 C AIGaN/AIN • WBG semiconductors can: – Operate at higher temperatures without “going intrinsic” 4 – Block higher voltages for a given thickness of material (breakdown voltage ∝ (Egap) ) – Switch at higher speeds due in part to higher saturation velocities – … and other WBG-material specific advantages To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 5 A Closer Look: SiC vs. Si • Overview 0 < CD < co Electron :E Saturation Velocity Electric Field [x107 cm/s] [MV/cm] Fast Switching Applications E si 1- 4H-SiC -- - ----------------, Melting Point Thermal Conductivity [x1000 °C] [W/cm/°C] High Temperature Applications SiC out-performs Si on 5 different parameters, lending itself to high-power, high-temperature, and fast-switching applications To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 6 A Closer Look: GaN vs. SiC vs. Si • Bandgap Energy ~- [eV] ~ '9~~ ~~- 0/4 ~ C"~ Q>~. '9& 0~ ~ Electron ' ' Electric Field Overview Saturation Velocity 0 < 7 [MV/cm] CD [x10 cm/s] < ro Fast Switching ~ Applications - Si - 4H-SiC - GaN_j Melting Point Thermal Conductivity [x1000 °C] [W/cm/°C] High Temperature Applications To date, GaN’s upper limit on voltage rating is dictated primarily by device degradation/reliability issues To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 7 A Closer Look: RF Performance • L.. • RF power amplifiers are critical for Q) Diamond radar and communications systems ~ Ga O 0 2 3 – Choice of semiconductor material will Cl. SiC depend in part on power and frequency needs Overview 0 GaN < • Plot on left is intended only to provide a general (1) idea of the capabilities of each material ro< InP :E Output Power Output Si GaAs FrequencyFrequency Future RF amplifiers may combine different semiconductor technologies for system optimization To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 8 Wide-Bandgap Technology Overview: Translation of Properties into Performance • Higher Blocking Voltage: Faster Switching Speeds & Lower Losses: • Reduced current for the same power • Smaller, lighter passive circuit – Smaller-gauge harnesses/cabling elements • Decreased design complexity • Smaller, lighter cooling elements – Reduced need for device stacking Power module NASA Solar Electric Propulsion: 2.7 tons mass savings by moving to higher voltage power management & distribution Toyota estimates 80% volume reduction of Source: Mercer, AIAA 2011-7252; Image: NASA Prius power control unit using SiC vs. Si Overview https://newsroom.toyota.co.jp/en/detail/2656842 (Image used with permission) High Power Density: • 5x – 10x smaller footprint for Ka-band power amplifier: 72% area RF power GaN vs. GaAs reduction & 4x power increase • Easier impedance matching using GaN vs. GaAs – lower circuit losses Image modified from: Kong, K. et al., IEEE CSICS, 2014 To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 9 Wide-Bandgap Technology Overview: The Space Radiation Environment • • Trapped radiation belts – High & variable flux of protons and electrons – Concerns include: • Total ionizing dose (TID) • Displacement damage dose (DDD) • Proton-induced single-event effects (SEE) TID • Solar Particle Events (SPE) DDD – Intermittent high flux of moderate- energy protons, electrons, and ions with atomic number Z = 1 to ~26 – Concerns include TID, DDD, and SEE TID, DDD, SEE Overview • Galactic Cosmic Rays (GCR) 0 < SEE Cl) < – Low flux of very high energy ions of ro Image modified from: :E all Z – Primary concern = SEE To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 10 Wide-Bandgap Technology Overview: “But I Heard that WBG Semiconductors are Rad-Hard!” • • “Inherent” radiation hardness of WBG semiconductors typically refers to their tolerance of total dose: – Both the ionization energy and threshold energy for defect formation (atomic bond strength) exceed that for Si • Must also consider the material density (interaction cross section) – Early WBG devices did not have gate oxides – For the same working voltage range, SiC and other doped WBG materials can have a higher doping concentration to decrease sensitivity to carrier removal – Operation of WBG devices at high temperature results in greater mobility of defects, reducing formation of defect complexes Overview 0 < CD c;;·< ~ To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 11 • SILICON CARBIDE POWER DEVICE RADIATION EFFECTS To be presented by J.-M. Lauenstein at the Radiation Effects on Components and Systems (RADECS) Topical Day, Gothenburg, Sweden, September 16, 2018 12 WBG RHA ~ co G) SiC Outline ::0 I )> • • Effects of radiation: 6H-SiC –
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