Influence of Interface trap distributions over the device characteristics of AlGaN/GaN/AlInN MOS‐HEMT using Cubic Spline Interpolation technique

Abstract

Traps present at the interface of oxide and barrier layers influence the device's DC and RF parameters. An investigation is carried out on the distribution of interface traps present in the AlGaN/GaN/AlInN Metal Oxide Semiconductor‐High Electron Mobility Transistor (MOS‐HEMT) structures. By incorporating Hafnium Oxide (HfO2) as a dielectric layer, the DC and RF parameters like current drive and Power‐Added Efficiency (PAE) for the device are evaluated. The Capacitance‐Voltage (C–V) curves showed a shift in its values upon increase in trap density, which attributes to the position of fermi level once the threshold voltage is reached. A theoretical estimation of interface trap densities revealed distributions in the magnitude of 9.52 × 1012 cm−2 eV−1 near the mid‐gap and around 3.4 × 1013 cm−2 eV−1 at the Conduction Band (CB) edge. Carrier concentration at the Two‐Dimensional Electron Gas (2DEG) influences the distribution of traps at the interface, which in turn affects the on‐resistance of the device. Cubic Spline Interpolation (CSI) technique is employed here to model the device parameters precisely. The higk‐K dielectric material causes a high cut‐off of 201 GHz for the MOS‐HEMT. There is about 42% improvement in the PAE compared to the conventional MOS‐HEMT device. The comparably low trap density values (1012 cm−2 eV−1) than the conventional ones, prove the high quality gate passivation features of the HfO2/AlGaN interface and could serve as a potential candidate for high power and microwave applications.