Substrate-Dependent Characteristics of AlGaN/AlN/GaN DH-HEMT: A Comprehensive Study

This paper investigates the performance of Dual-Channel (DC) or Dual-Heterostructure (DH) Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.21</inf>Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.79</inf>N/AlN/GaN High Electron Mobility Transistors (HEMT) using three different substrate materials: Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>, GaN, and Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>. TCAD simulations are employed to compare the critical device characteristics, including Id (drain current) versus V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> (gate voltage), Id (drain current) versus V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</inf> (drain voltage), transconductance (gm) versus V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf>, and cutoff frequency (fT) versus V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf>. This comparative analysis aims to identify the optimal substrate material for DH-HEMTs based on their electrical performance. The DH-HEMT structure itself incorporates a thin AlN layer sandwiched between AlGaN and GaN layers [1]. This design creates a double channel for electrons, enhancing carrier confinement and potentially leading to superior device characteristics compared to single-channel HEMTs. By exploring different substrate materials, this study seeks to optimize the overall performance of DH-HEMTs for potential applications in high-frequency and power electronics.