University of Connecticut OpenCommons@UConn Doctoral Dissertations University of Connecticut Graduate School 5-11-2013 II–VI Epitaxial Films in Nonvolatile memory, 3-state FETs, and Solar Cells Ernesto Suarez
[email protected] Follow this and additional works at: https://opencommons.uconn.edu/dissertations Recommended Citation Suarez, Ernesto, "II–VI Epitaxial Films in Nonvolatile memory, 3-state FETs, and Solar Cells" (2013). Doctoral Dissertations. 92. https://opencommons.uconn.edu/dissertations/92 II–VI Epitaxial Films in Nonvolatile memory, 3-state FETs, and Solar Cells Ernesto Suarez PhD University of Connecticut 2013 ABSTRACT This thesis presents design and fabrication of improved performance FETs, nonvolatile memories, and solar cells. The key feature is the use of wide band gap II-VI quantum well layers and/or quantum dots which are grown using UltraViolet (UV) low temperature Metal-Organic Chemical Vapor Deposition (MOCVD) heteroepitaxy. These layers serve as an insulating substitute for gate insulators such as SiO 2 or HfO 2. The motivation behind using II-VI lattice- matched gate dielectrics is two-fold: (1) to reduce interface states and their adverse impact on threshold voltage, in particular its variation from device-to- device in sub-22nm structures, and (2) to utilize the higher dielectric constant of ZnMgS with respect to SiO 2. The material structure for this tunneling layer is ZnS/Zn 0.95 Mg 0.05 S/ZnS. A 5 nm layer of ZnSe is grown on both sides of this stack to aide with heteroepitaxial adhesion. Auger SIMS surface scan and depth profile data is presented. This ZnSe layer is less than the critical layer thickness therefore is negligible to additional dislocations due to lattice mismatch strain.