Analytical modeling of channel potential and threshold voltage of triple material gate AlGaN/GaN HEMT including trapped and polarization‐induced charges

Abstract

We have developed an analytical model of channel potential and threshold voltage of a gate-engineered heterostructure transistor, triple material gate aluminum gallium nitride (AlGaN)/gallium nitride (GaN) high electron mobility transistor (HEMT). Two steps in channel potential profile lead to suppression of short channel effects. For accurate modeling of the device, spontaneous and piezoelectric polarization-induced charges at the AlGaN/GaN interface and temperature and mole fraction dependence of device parameters are considered. The impact of trapped charges formed because of process defects during device growth is also analyzed. The device performance is studied with the variation in device parameters, and superior performance of triple material gate HEMT over other HEMT structures is observed in terms of reduced short channel effects and enhanced carrier velocity. Results from the proposed analytical model are validated against the data obtained from a commercially available numerical device simulator.

Computational Analysis of Joule Heating Effect in Triple Material Gate AlGaN/GaN High Electron Mobility Transistor

“…Increased Joule heating effect resulting from higher current density is responsible for greater channel temperature in case of TMG HEMT with smaller L1. Higher current density is the consequence of minimized channel potential barrier for small L1 case, as described in (9). More electrons can reach the drain end from source terminal through the channel which lead to increased drift current.…”

“…Polarization induced charges affect Joule heating in AlGaN/GaN HEMT which can be analyzed from Figure 6. Spontaneous and piezoelectric induced charges at AlGaN and GaN layers depend on Al mole fraction and can be calculated from (9,23). Figure 6 shows maximum temperature in the channel for devices with two different mole fractions of Al in AlGaN.…”

“…Besides, high saturation carrier velocity of GaN facilitates superior device performance at high frequency applications (8). Recently, a novel AlGaN/GaN HEMT structure named triple material gate (TMG) HEMT has been proposed in (9) in which the gate contact is composed of three metals with different work functions. This TMG HEMT ensures high carrier velocity and better suppression of short channel effects.…”

Influence of Tunable Work Function on SOI-based DMG Multi-channel Junctionless Thin Film Transistor

“…This causes a reduction in hot carrier effect at the drain side, which creates a rise in the average electric field under the gate. There is a reduction in the ability of localized charges to increase drain resistance, due to which their lifetime is increased [7,8]. In [9], by building DMGs in cylindrical nanowires and analyzing with various gate oxides, the superiority of HfO2 dielectric over other oxide layers has been established.…”

Analysis of Junctionless Nanowire Transistor with Heterojunction, Metal Nitride and Dual Metal Gate

“…The peak electric field at the drain end is reduced in the DMG structure, resulting in an increase in the average electric field under the gate. This enables improved lifetime of the device [12,13]. The superiority of HfO2 dielectric over other oxide layers has been proven in [14,15] by creating dual metal gates in cylindrical nanowires and analyzing with various gate oxides.…”