Umesh K. Mishra
University of California, Santa Barbara
929 Papers
10.5K Citations
Umesh K. Mishra is an academic researcher from University of California, Santa Barbara. The author has contributed to research in topics: Gallium nitride & High-electron-mobility transistor. The author has an hindex of 96, co-authored 912 publications. Previous affiliations of Umesh K. Mishra include North Carolina State University & University of California.
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Papers
In-situ metalorganic chemical vapor deposition and capacitance-voltage characterizations of Al2O3 on Ga-face GaN metal-oxide-semiconductor capacitors
Xiang Liu,Ramya Yeluri,J.K. Kim,Shalini Lal,Ajay Raman,Cory Lund,Steven Wienecke,Jing Lu,Matthew A. Laurent,Stacia Keller,Umesh K. Mishra +10 more
TL;DR: In this paper, the in-situ metalorganic chemical vapor deposition of Al2O3 on Ga-face GaN metaloxide-semiconductor capacitors (MOSCAPs) is reported.
Effect of ohmic contacts on buffer leakage of GaN transistors
Yuvaraj Dora,Arpan Chakraborty,Sten Heikman,L. McCarthy,Sarah L. Keller,Steven P. DenBaars,Umesh K. Mishra +6 more
TL;DR: In this article, the effect of alloyed ohmic contacts on buffer leakage of GaN transistors was investigated and it was shown that the increased buffer leakage is due to the nature of the alloyed contacts and can be minimized if they are screened by the Si doping or by the two-dimensional electron gas.
SiN x /(Al,Ga)N interface barrier in N-polar III-nitride transistor structures studied by modulation spectroscopy
TL;DR: While a gradual decrease in carrier concentration with decreasing channel thickness is expected for N-polar structures, experimentally a sudden drop in the ns values is observed for samples with very thin channels, with additional loss in charge associated with a change in the SiNx/AlGaN interface Fermi level at very thin channel thicknesses.
Estimation of Hot Electron Relaxation Time in GaN Using Hot Electron Transistors
Sansaptak Dasgupta,Jing Lu,Nidhi,Ajay Raman,Christophe A. Hurni,Geetak Gupta,James S. Speck,Umesh K. Mishra +7 more
TL;DR: In this paper, the authors reported the first estimation of hot electron relaxation time in GaN using electrical measurements, which matched well with theoretically predicted relaxation times based on longitudinal optical (LO) phonon scattering.