Analytical study of effect of energy band parameters and lattice temperature on conduction band offset in AlN/Ga2O3 HEMT

Apart from other factors, band alignment led conduction band offset (CBO) largely affects the two dimensional electron gas (2DEG) density ns in wide bandgap semiconductor based high electron mobility transistors (HEMTs). In the context of assessing various performance metrics of HEMTs, rational estimation of CBO and maximum achievable 2DEG density is critical. Here, we present an analytical study on the effect of different energy band parameters-energy bandgap and electron affinity of heterostructure constituents, and lattice temperature on CBO and estimated 2DEG density in quantum triangular-well. It is found that at thermal equilibrium, ns increases linearly with ?EC at a fixed Schottky barrier potential, but decreases linearly with increasing gate-metal work function even at fixed ?EC, due to increased Schottky barrier heights. Furthermore, it is also observed that poor thermal conductivity led to higher lattice temperature which results in lower energy bandgap, and hence affects ?EC and ns at higher output currents.

High-performance AlGaN double channel HEMTs with improved drain current density and high breakdown voltage

In this work, AlGaN double channel heterostructure is proposed and grown by metal organic chemical vapor deposition (MOCVD), and high-performance AlGaN double channel high electron mobility transistors (HEMTs) are fabricated and investigated. The implementation of double channel feature effectively improves the transport properties of AlGaN channel heterostructures. On one hand, the total two dimensional electron gas (2DEG) density is promoted due to the double potential wells along the vertical direction and the enhanced carrier confinement. On the other hand, the average 2DEG density in each channel is reduced, and the mobility is elevated resulted from the suppression of carrier-carrier scattering effect. As a result, the maximum drain current density (I max ) of AlGaN double channel HEMTs reaches 473 mA/mm with gate voltage of 0V. Moreover, the superior breakdown performance of the AlGaN double channel HEMTs is also demonstrated. These results not only show the great application potential of AlGaN double channel HEMTs in microwave power electronics, but also develops a new thinking for the studies of group III nitride based electronic devices.

High-performance AlGaN double channel HEMTs with improved drain current density and high breakdown voltage

In this work, for the first time, AlGaN double channel heterostructure is proposed and grown by metal organic chemical vapor deposition (MOCVD), and high-performance AlGaN double channel high electron mobility transistors (HEMTs) are fabricated and investigated. The implementation of double channel feature effectively improves the transport properties of AlGaN channel heterostructures. On one hand, the total two dimensional electron gas (2DEG) density is promoted due to the double potential wells along the vertical direction and the enhanced carrier confinement. On the other hand, the average 2DEG density in each channel is reduced, and the mobility is elevated resulted from the suppression of carrier-carrier scattering effect. As a result, the maximum drain current density (Imax) of AlGaN double channel HEMTs reaches 473 mA/mm with gate voltage of 0V. Moreover, the superior breakdown performance of the AlGaN double channel HEMTs is also demonstrated. These results not only show the great application potential of AlGaN double channel HEMTs in microwave power electronics, but also develops a new thinking for the studies of group III nitride based electronic devices.

A Physics-Based Analytical Model for MgZnO/ZnO HEMT

In this paper, a physics-based compact model is developed for novel MgZnO/ZnO high-electron-mobility transistor (HEMT). Poisson’s equation coupled with 1D Schrödinger equation is solved self-consistently in the triangular quantum well to derive an expression of two-dimensional electron gas (2DEG) density with respect to gate voltage at the heterointerface of barrier (MgZnO) and buffer (ZnO) layers. A compact mathematical framework has been devised further for the first time for ZnO-based HEMT to the best of our knowledge using the expression of 2DEG density to compute surface potential, gate charge, gate current, gate capacitance, current–voltage characteristics, output conductance, transconductance and cut-off frequency with respect to gate voltage and along with the drain–source output resistance [Formula: see text].

Modeling of 2DEG characteristics of InxAl1−xN/AlN/GaN-Based HEMT Considering Polarization and Quantum Mechanical Effect

A comprehensive model for 2DEG characteristics of InxAl1−xN/AlN/GaN heterostructure has been presented, taking both polarization and bulk ionized charge into account. Investigations on the 2DEG density and electron distribution across the heterostructure have been carried out using solutions of coupled 1-D Schrödinger-Poisson equations solved by an improved iterative scheme. The proposed model extends a previous approach allowing for estimating the quantum mechanical effect for a generic InAlN/GaN-based HEMT within the range of the Hartree approximation. A critical AlN thickness (~2.28 nm) is predicted when considering the 2DEG density in dependence on a lattice matched In0.17Al0.83N thickness. The obtained results present in this work provide a guideline for the experimental observation of the subband structure of InAlN/GaN heterostructure and may be used as a design tool for the optimization of that epilayer structure.