VTH Instability of -GaN Gate HEMTs Under Static and Dynamic Gate Stress

• Published in: IEEE electron device letters Vol. 39; no. 10; pp. 1576 - 1579
• Main Authors: He, Jiabei, Tang, Gaofei, Chen, Kevin J.
• Format: Journal Article
• Language: English
• Published: IEEE 01.10.2018
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">p -GaN; Aluminum gallium nitride; Charge carrier processes; Delays; Dynamic gate stress; HEMTs; Logic gates; PBTI; Schottky gate contact; Stress; threshold voltage shift; Wide band gap semiconductors
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2018.2867938

The impacts of static and dynamic gate stress on the threshold voltage (<inline-formula> <tex-math notation="LaTeX">{V}_{\text {TH}} </tex-math></inline-formula>) instability in Schottky-type <inline-formula> <tex-math notation="LaTeX">{p} </tex-math></inline-formula>-GaN gate AlGaN/GaN heterojunction field-effect transistors are experimentally investigated. <inline-formula> <tex-math notation="LaTeX">{V}_{\text {TH}} </tex-math></inline-formula> shifts negatively under large positive bias static stress (<inline-formula> <tex-math notation="LaTeX">{V}_{\text {G}}\_ {\text {stress}} > 5 </tex-math></inline-formula> V) by adopting conventional quasi-static characterization techniques. In contrast, <inline-formula> <tex-math notation="LaTeX">{V}_{\text {TH}} </tex-math></inline-formula> under fast-dynamic-stress exhibits positive shift, and a positive frequency dependence occurs within a wide range of frequency from 10 Hz to 1 MHz. The different <inline-formula> <tex-math notation="LaTeX">{V}_{\text {TH}} </tex-math></inline-formula> instability behavior under static and dynamic stress mainly originates from the time-dependent charges (electrons and holes) storage/release mechanisms in the <inline-formula> <tex-math notation="LaTeX">{p} </tex-math></inline-formula>-GaN layer, which is floating in the Schottky-type <inline-formula> <tex-math notation="LaTeX">{p} </tex-math></inline-formula>-GaN gate HEMT.