Positive and negative threshold voltage instabilities in GaN-based transistors

Dynamic characterization of SiC and GaN devices with BTI stresses

“…To date there have been relatively few investigations of BTI in commercial GaN devices compared to the numerous studies on SiC [2][3][4]. Experiments have been performed on custom made insulated gate GaN MIS-HEMTs [13] and more recently on commercially available GaN devices [14]. In [14] the authors concluded that no observable VTH shift, change in drain leakage current or ON-state resistance was evident after VGS gate stress up to 7 V. However, at about 10 V, the gate current increased significantly and the device failed.…”

“…Experiments have been performed on custom made insulated gate GaN MIS-HEMTs [13] and more recently on commercially available GaN devices [14]. In [14] the authors concluded that no observable VTH shift, change in drain leakage current or ON-state resistance was evident after VGS gate stress up to 7 V. However, at about 10 V, the gate current increased significantly and the device failed. In this section the impact of BTI on the switching transients is evaluated for both commercially available SiC MOSFETs and GaN HEMTs.…”

Exploration of Physicochemical Mechanism for Negative Bias Temperature Instability in GaN‐HEMTs by Extracting Activation Energy of Dislocations

“…While intensive efforts have been made to optimize it from the perspective of manufacturing process or selected materials, [ 45,51,52 ] insufficient attention has been devoted to fundamental understanding of the intrinsic mechanisms. Some studies [ 41–46 ] attributed the degradation to the charge and discharge process of defects at the interface of GaN buffer layer and dielectric layer, while others [ 47–50 ] considered the degradation cause is not only the interface defects but also possible defects in inner dielectric layer and buffer layer. The origin of their instability, either induced by dislocations, or pertaining to the thermodynamically unstable nature, are still obscure and remain unsolved.…”

“…While intensive efforts have been made to optimize it from the perspective of manufacturing process or selected materials, [45,51,52] insufficient attention has been devoted to fundamental understanding of the intrinsic mechanisms. Some studies [41][42][43][44][45][46] attributed the degradation to the charge and discharge process of defects at the interface of GaN buffer layer and dielectric layer, while others [47][48][49][50] considered the degradation cause is not only the interface…”

“…[32] Although the NBTI problem was first noticed and mainly discussed in p-MOSFET devices, [33][34][35][36] it also perplexes depletion-mode or normally-ON GaN-HEMTs which is the most frequently used GaN device. [37][38][39][40][41][42][43][44] NBTI-related issues in depletion-mode GaN-HEMTs with different kinds of dielectric layer have been investigated in a series of researches. [41,[45][46][47][48][49][50] The NBTI-induced reliability issues in GaN-HEMTs have been acknowledged as a major concern that contributes to the operational instability.…”