Eur. Phys. J. Appl. Phys. 100, 7 (2025)
https://doi.org/10.1051/epjap/2025006

Original Article

Theoretical investigations on the confinement properties of InAlN/GaN/AlGaN heterostructures employing Al_xGa_1-xN as back-barrier

¹ School of Mechanical and Electrical Engineering, Handan University, Handan 056006, P.R. China
² Handan Polytechnic College, Handan 056001, P.R. China
³ Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P.R. China
⁴ School of Information and Electrical Engineering, Hebei University of Engineering, Handan 056038, P.R. China

^* e-mail: lilirong0917@163.com

Received: 12 September 2024
Accepted: 11 February 2025
Published online: 4 March 2025

Abstract

This study focuses on the InAlN/GaN/AlGaN heterostructures, initiating from polarization energy band tailoring engineering to establish a theoretical model. An Al_xGa_1-xN back-barrier is introduced to augment the confinement ability of the two-dimensional electron gas (2DEG) in conduction channel, enhance power output, and reduce leakage in the buffer layer. The primary investigation explores the impact of GaN channel layer’s thickness d_GaN and the Al content x of the Al_xGa_1-xN back-barrier layer on the confinement properties and sheet density of 2DEG. It also examines the formation mechanisms of two-dimensional hole gas (2DHG) and the structural design requirements of back-barrier. Theoretical research indicates that as the x or d_GaN increases, the confinement properties of the 2DEG significantly improve, provided a certain critical condition is met. Excessive x or d_GaN induces the formation of 2DHG at the GaN/AlGaN interface. The findings demonstrate that maintaining the d_GaN below a critical value, given a certain x, can enhance 2DEG confinement properties while suppressing 2DHG formation. This research offers a robust theoretical foundation for the development of GaN-based materials and HEMT device fabrication.