Influence of Buffer Carbon Doping on Pulse and AC Behavior of Insulated-Gate Field-Plated Power AlGaN/GaN HEMTs

Abstract

Pulse behavior of insulated-gate double-field-plate power AlGaN/GaN HEMTs with C-doped buffers showing small current-collapse effects and dynamic RDS,on increase can accurately be reproduced by numerical device simulations that assume the CN-CGa autocompensation model as carbon doping mechanism. Current-collapse effects much larger than experimentally observed are instead predicted by simulations if C doping is accounted by dominant acceptor states. This suggests that buffer growth conditions favoring CN-CGa autocompensation can allow for the fabrication of power AlGaN/GaN HEMTs with reduced current-collapse effects. The drain-source capacitance of these devices is found to be a sensitive function of the C doping model, suggesting that its monitoring can be adopted as a fast technique to assess buffer compensation properties

Optimisation of a carbon doped buffer layer for AlGaN/GaN HEMT devices

“…Recent studies based on drift diffusion simulations [9] predicted strong current collapse phenomena induced by a carbon doped GaN BL, taking into account only the C N energy level at 0.90 eV above the valence band maximum. Verzellesi et al [10] pointed out by numerical device simulations that large variations of pulsed performances of AlGaN/GaN HEMTs can be obtained by Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jcrysgro changing the model of compensation mechanism in a carbon doped GaN buffer layer, with a given carbon profile.…”

Control of Buffer-Induced Current Collapse in AlGaN/GaN HEMTs Using SiNx Deposition

“…The location of this trapped charge has been reported as being above the channel [2] and below the channel in the carbon-doped GaN layer (C:GaN) [3]. Previous work has shown several ways to control increased dynamic on-resistance such as introducing fieldplates [4], making changes to the SiNx deposition process [5,6] and changing GaN epitaxial growth [7,8]. Until now these two trapping locations were thought to be independently controlled, however this work demonstrates that changes to the bulk C:GaN layer trapping can be caused by modifying the surface passivation process [9].…”

High‐resistance GaN‐based buffer layers grown by a polarization doping method

“…Other than these, the most widely method to inhibited the drain leakage is impurity doping. The acceptor impurity, such as C, Fe, Mg and Mn, is intentionally introduced to provide holes to compensate the background electrons [7][8][9][10]. However, many research show that intentional doping could bring the high density defect traps, which result in an increase in the ON-resistance during switching operation,so-called current collapse [11,12].…”