Identification of Semi-ON-State Current Collapse in AlGaN/GaN HEMTs by Drain Current Deep Level Transient Spectroscopy
Yixu Yao, Sen Huang, Qimeng Jiang, Xinhua Wang, Lan Bi, Wen Shi, Fuqiang Guo, Tiantian Luan, Jie Fan, Haibo Yin, Wei Ke, Yingkui Zheng, Jingyuan Shi, Yankui Li, Qian Sun, Xinyu Liu
Abstract
A drain-controlled current-mode deep level transient spectroscopy (I-DLTS), was developed for investigation of Semi-ON-state current collapse in AlGaN/GaN high electron mobility transistors (HEMTs). By inserting a graded AlGaN back-barrier between the GaN channel and AlGaN buffer layer, hot-electron effect induced charging of buffer traps is effectively blocked, which contributes to a remarkable suppressed current collapse in AlGaN/GaN HEMTs under Semi-ON-state stress. A broad-distributed electron trap <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\text {T1}}$ </tex-math></inline-formula> , which features an energy level depth <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\text {C}}$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\text {T}}$ </tex-math></inline-formula> and apparent capture cross section <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\sigma }_{\text {T}}$ </tex-math></inline-formula> of 0.25 ± 0.05 eV and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.0\,\, {\pm } 1.0 {\times } 10^{-18}$ </tex-math></inline-formula> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , was verified to locate in the AlGaN buffer layer by I-DLTS. A combination of pulsed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> and I-DLTS measurements, could be an effective method for in-situ study of current collapse mechanism in AlGaN/GaN HEMTs.