Understanding traps locations and impact on AlGaN/GaN HEMT by LFN noise & transient measurements, and T-CAD simulations

Abstract

Nitride technologies are widely used for high frequency and high power electronics, and raise a growing interest for robust low noise receivers. However, the stability of DC and RF performances are difficult to achieve, at a cost of technological trade-offs. Among the problems not totally mastered, traps and charges located in the active regions of the transistor induce a large variety of electrical behaviours; some traps are not harmful as they do not affect the transistor performances, some can impact the signal integrity or can raise reliability problems. The paper addresses a method based on low frequency noise (LFN) and random telegraph noise (RTN) measurements crossed with transient measurements and T-CAD simulations to locate the defects, and to evaluate their actual impact on the device integrity. This study is realized on virgin and stressed AlGaN/GaN High Electron Mobility Transistors (HEMT). Charges under the gated zone and at the AlGaN/GaN-passivation interface are identified by noise measurements and by T-CAD simulations.