A Current-Transient Methodology for Trap Analysis for GaN High Electron Mobility Transistors

Abstract

Abstract-Trapping is one of the most deleterious effects that limit performance and reliability in GaN HEMTs. In this paper, we present a methodology to study trapping characteristics in GaN HEMTs that is based on current-transient measurements. Its uniqueness is that it is amenable to integration with electrical stress experiments in long-term reliability studies. We present the details of the measurement and analysis procedures. With this method, we have investigated the trapping and detrapping dynamics of GaN HEMTs. In particular, we examined layer location, energy level, and trapping/detrapping time constants of dominant traps. We have identified several traps inside the AlGaN barrier layer or at the surface close to the gate edge and in the GaN buffer.

Trapping Analysis of AlGaN/GaN Schottky Diodes via Current Transient Spectroscopy

“…However, usually a large number of exponentials needs to be used to construct an A i = f (τ i ) diagram, e.g., Joh and del Alamo used 100 exponentials [19], and Hu et al as many as 400 [14]. As is shown below, we were able to fit our data satisfactorily with only three exponentials.…”

“…Measurement was performed in a temperature range between 25 and 150˝C using a heated plate and an ATT Systems A150 temperature controller. (e.g., [14,17,20,21]) and between 0.71 and 0.82 eV (e.g., [1,9,19,[22][23][24]) were the most commonly reported. Unfortunately, their origin remains ambiguous.…”

“…Other commonly used methods are based on the measurement of frequency-dependent conductance [15], low-frequency noise [16], transconductance non-linearity [17], and capacitance-voltage characterization concerning hysteresis [18]. As an extension of the current-mode DLTS, current-transient analysis utilizing a multiexponential decay fitting was also proposed [19]. However, such a procedure has not been generally used at present due to the necessity of using a more complicated fitting technique.…”

Trapping characteristics and parametric shifts in lateral GaN HEMTs with SiO<inf>2</inf>/AlGaN gate stacks

“…In this work, a modified current transient [4] with regularization techniques [5], [6 characterize the recovery transients. We n transient methods are conceptually similar to Grasser in [7] with comparable techniques app [8] to HEMT structures.…”

Investigation of Buffer Traps in AlGaN/GaN Heterostructure Field-Effect Transistors Using a Simple Test Structure

“…However, recent reports show that the bulk traps in the semi-insulating GaN buffer also can cause the serious current collapse in AlGaN/GaN HFETs [3]. Previously, the bulk traps in the semi-insulating GaN buffer have been mainly investigated using the capacitance-mode deep level transient spectroscopy (C-DLTS) [4], the backgating current transient spectroscopy [5,6], and the drain current transient method [7][8][9]. C-DLTS is a powerful and well-established technique for the extraction of bulk traps in semiconductor devices.…”