A Novel Gate-to-Source ESD Protection Clamp for GaN HEMT
Yijun Shi, Yiqiang Chen, Yun Huang, Zhiyuan He, Wanjun Chen, Ruize Sun, Bin Yao, Hongyue Wang, Qingzhong Xiao, Guoguang Lu, Bo Zhang
Abstract
In this work, a novel GaN electrostatic discharge (ESD) protection clamp is proposed for enhancing the gate structure’s ESD reliability of the conventional (Con.) p-GaN high-electron-mobility transistor (HEMT). The proposed clamp features a floating p-GaN structure and a pF-grade capacitor, which is in parallel connection between the anode electrode and the floating p-GaN structure ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${C}_{\text {GA}}$ </tex-math></inline-formula> ). It is demonstrated that the proposed clamp not only possesses a low triggering voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t} < {10}$ </tex-math></inline-formula> V) but also can withstand a relatively high second breakdown current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{s} \sim 6$ </tex-math></inline-formula> A) in the transient ESD event. Hence, the proposed clamp can usefully discharge the transient electrostatic charges accumulated at the gate structure of the Con. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}$ </tex-math></inline-formula> -mode p-GaN HEMT and clamp its potential at a low value, thereby enhancing its ESD reliability and avoiding the gate-to-source ESD damage. It is also found that the clamp’s <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{s}$ </tex-math></inline-formula> have a strong correlation with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${C}_{\text {GA}}$ </tex-math></inline-formula> . Thus, through changing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${C}_{\text {GA}}$ </tex-math></inline-formula> , the clamp will possess the desired <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{s}$ </tex-math></inline-formula> ’s. In addition, the proposed clamp can be fabricated on the Con. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}$ </tex-math></inline-formula> -mode p-GaN HEMT platform, making the HEMT’s ESD design more convenient.