Impact and Analysis of Al Composition in Barrier and Buffer regions of AlxGA(1–x)N/GaN HEMT Device using TCAD Simulations

In this study, we employ Technology Computer Aided Design (TCAD) simulations to understand the impact of Al composition (x) in AlxGa(1–x)N buffer and barrier layers on GaN High Electron Mobility Transistors (HEMTs) on silicon substrates. We uncover the critical role of Al composition in enhancing the quantum well at the AlxGa(1–x)N/GaN interface, effectively confining electrons and directing the two-dimensional electron gas (2DEG). Our simulations yield impressive results, including a high electron mobility of 1460 cm2/Vs and an electron density of 7.5 × 1019 cm–3. Moreover, as we increase the Al composition in the barrier layer from 0.15 to 0.30, we observe a substantial rise in the breakdown voltage, a crucial parameter for optoelectronic and quantum devices. Specifically, the breakdown voltage reaches 618 V, accompanied by a threshold voltage of 3 V and a drain current of 0.51 A/mm at 0 V gate voltage. These findings not only advance our understanding of AlxGa(1–x)N/GaN heterostructures but also underscore their potential in driving the improvement of future optoelectronic and quantum devices, making them highly relevant to the field of optoelectronic and quantum devices.