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Device characteristics of enhancement mode double heterostructure DH‐HEMT with boron‐doped GaN gate cap layer for full‐bridge inverter circuit
Author(s) -
Mohanbabu A.,
Mohankumar N.,
Godwin Raj D.,
Sarkar Partha,
Saha Samar K.
Publication year - 2017
Publication title -
international journal of numerical modelling: electronic networks, devices and fields
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.249
H-Index - 30
eISSN - 1099-1204
pISSN - 0894-3370
DOI - 10.1002/jnm.2276
Subject(s) - materials science , optoelectronics , schottky barrier , subthreshold slope , doping , high electron mobility transistor , heterojunction , threshold voltage , barrier layer , breakdown voltage , transistor , electrical engineering , layer (electronics) , voltage , nanotechnology , diode , engineering
This paper reports a systematic theoretical study of Al 0.23 Ga 0.77 N/GaN/Al x Ga 1‐x N double‐heterojunction high electron mobility transistors (DH‐HEMTs) with a boron‐doped GaN cap layer under the gate. Boron containing GaN is a desired replacement for Schottky gate in DH‐HEMT to improve the resistivity and surface qualities of GaN cap with good structural properties, and the influence of polarization field in the GaN cap layer can be used to lift up the conduction band for normally OFF operation of the device. This study shows that the B‐doped GaN cap layer offers excellent device characteristics such as high threshold voltage V T of 1.92 V, steep subthreshold slope of ~ 72 mV/dec, high ON/OFF drain current ratio of ~ 10 7 , extremely low subthreshold drain current I ds,LL ~ 10 −9 A/mm, and low gate leakage current, I gs,LL less than 10 −15 A/mm. For an Al 0.07 Ga 0.93 N back‐barrier/buffer, a high OFF‐state breakdown voltage ( V BR,OFF ) of 865 V is achieved at I ds = 1 mA/mm and V gs = 0 V with substrate grounded and gate‐to‐drain distance and gate field plate length of 10 and 5 μm, respectively. The simulated high V T and V BR,OFF values are achieved due to the presence of increased back‐barrier height of the Al x Ga 1‐x N buffer and high Schottky barrier between the Boron‐doped GaN cap and gate metal. Finally, a DC to AC full‐bridge inverter circuit is designed to evaluate the benefit of B‐doped DH‐HEMTs based switching devices for an ultra‐low‐loss inverter circuit.