Dielectric and Gate-Stack Engineering in N-Polar GaN Deep Recess MISHEMTs
Abstract
Dielectric and Gate-Stack Engineering in N-Polar GaN Deep Recess MISHEMTsStatement of WorkFunds are provided to develop n-polar GaN HEMTs for RF applicationsThe PI is Prof. Umesh Mishra at the University of California, Santa Barbara.This is a 36-month grant.This grant will leverage results of the DEFINE MURI to investigate new gate dielectrics in metal insulator HEMTs (MISHEMT). The gate barrier in N-polar deep recess MISHEMTs will be investigated. Recent advances in the growth of MOCVD dielectrics on GaN will be leveraged to optimize the combination of AlGaN cap layer and gate dielectric (the gate stack) to provide robust device performance. By mapping the gate stack design space through material thickness and composition variation, devices will be developed to target RF operation at Ka-band and above.ObjectiveExploit emerging dielectric films in metal insulator gate structures in nitrogen polar MISHEMT to suppress gate leakage current and suppress RF dispersion for improved PAE and power density.ApproachOptimization of AlGaN and Dielectric Regrowth on N-Polar GaN Investigate the range of AlxSiyOz composition and thickness for breakdown and reliability performance when grown on a N-polar AlGaN barrier. Initial material evaluation will be performed using In-dot Hall and MOS diode C-V and I-V measurements.Studies will also be conducted examining the regrowth of AlGaN in the etched recess of a NPDR device. This may include digitally etching of an existing AlGaN barrier before regrowth, inclusion of a GaN interlayer, and/or growing directly on existing AlGaN. Following the AlGaN regrowth a gate dielectric will be added in-situ.Implementation into full device. Based on results of initial materials study promising AlGaN cap and dielectric combinations will be implement into a full mm-wave NPDR device. DC and RF performance of the device will be evaluated using DC I-V, small signal RF, and pulsed I-V measurements. Large signal load pull measurements will be investigated for frequencies between 10 and 94 GHz.Merit / RelevanceThis effort builds on two prior D&I projects, nitrogen-polar W-band devices and the DEFINE MURI (dielectrics). This effort will investigate advanced thin film dielectrics in nitrogen polar HEMTS. If this is successful, then a significant improvement in device properties and device stability is expected. This will to significant performance advances for naval mm-wave sensors and communication systems
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 30, 2016
- Source ID
- N000141612933
Entities
People
- Umesh Mishra
Organizations
- Office of Naval Research
- United States Navy
- University of California, Santa Barbara