Characterization of Dynamic Threshold Voltage in Schottky-Type <i>p</i>-GaN Gate HEMT Under High-Frequency Switching
Kailun Zhong, Han Xu, Zheyang Zheng, Junting Chen, Kevin J. Chen
Abstract
The dynamics of the intrinsic threshold voltage ( V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) shift in 650-V Schottky-type p-GaN gate HEMT under high-frequency switching is investigated by a bootstrap voltage clamping circuit in which the GaN HEMT serves as the key bootstrapping device. This new testing setup covers a wide range of OFF-state drain bias ( V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DSQ</sub> ) up to 400V, a short OFF-to-ON (or stress-to-sense) delay ( T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">delay</sub> ) of 60ns, and a high switching frequency ( f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sw</sub> ) up to 2MHz. The dynamic V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> 's dependences on V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DSQ</sub> and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sw</sub> are characterized by this testing setup. A higher V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DSQ</sub> (up to 400V) results in a larger dynamic V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> shift (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ). The △V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> exhibits a gradually increasing trend under the continuous high-frequency switching mode. In addition, after continuous switching operation for 200μs, the maximum △V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> shows no f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sw</sub> dependence with a wide range of frequency from 50kHz to 2MHz.