Simulation of a high-performance enhancement-mode HFET with back-to-back graded AlGaN layers

Abstract

A novel three-dimensional hole gas (3DHG) enhancement-mode (E-mode) heterostructure fieldeffect transistor (HFET) is proposed and investigated. It features back-to-back graded AlGaN (BGA) barrier layers consisting of a positive-graded AlGaN layer and a negative-graded AlGaN layer, which form polarization gradient and subsequently induce the three-dimensional electron gas (3DEG) and 3DHG in the positiveand negative-graded AlGaN layers, respectively. The source and drain are located at the same side of the metal-insulator-semiconductor (MIS) trench gate, and the source is in contact with the HfO 2 gate insulator. First, the on-state current is significantly improved owing to the high-density 3DEG in the positive-graded AlGaN. Next, the vertical conductive channel between the source and 3DEG is blocked by the 3DHG, thereby realizing the E-mode. The threshold voltage (V th) can be modulated by a partial doping conductive channel. Subsequently, a high breakdown voltage (BV) is obtained, because the polarization junction formed by the polarization charges assists in depleting the drift region in the off-state. Next, the BGA-HFET is smaller than the conventional HFET (Con-HFET) owing to the special location of the source. The BV of the proposed HFET sharply increases to 919 V from 39 V of the Con-HFET with the same gate-drain spacing, and the saturation drain current is increased by 103.5%.

Interplay Between γ–Ray Irradiation and 3DEG for Dosimeter Applications

“…The group reports a significant enhancement in the drain current metrics in comparison to the conventional counterpart. Further studies on the architecture [19] reveal an enhancement in the OFF -state breakdown characteristics of the proposed architecture by 23 times compared to the conventional architecture, considering similar gate -drain spacings and physical gate lengths. Deng et al [20] further proposed an enhancement to the original stack by incorporating a GaN buffer between the positive and negative graded AlGaN layers.…”

“…The process recipe for the Virtual Fabrication of DUT through TCAD presented in this section, is an extension of the work reported by Peng et al [19]. Starting with the standard wafer cleansing procedure, the epi layer stack is grown in accordance with the structure depicted in Fig.…”

Analysis and simulation of bulk polarization mechanism in p-GaN HEMT with AI component gradient buffer layer

“…Therefore, obtaining a high resistance buffer without introducing other defects or parasitic channels is significant for GaN devices. Through investigation, polarization induced hole doping is applied to p-GaN HEMT buffer layer in this paper [15][16][17][18][19][20]. The positive polarization induced charge generated by the gradient Al component Al x Ga 1−x N buffer compensates the background electrons [10,21].…”