p-GaN Gate HEMTs on 6-Inch Sapphire by CMOS-Compatible Process: A Promising Game Changer for Power Electronics
Zhanfei Han, Xiangdong Li, Jian Ji, Long Chen, Lezhi Wang, Zhibo Cheng, Weitao Yang, Shuzhen You, Zilan Li, Yue Hao, Jincheng Zhang
Abstract
The ≥ 650 V power electronics market penetration by GaN HEMTs on Si has been impeded by the GaN buffer. Recently, GaN-on-sapphire, a promising solution, attracts great attentions. In this work, p-GaN gate HEMTs are successfully manufactured on 6-inch sapphire by CMOS-compatible process in our pilot line. Device process modules of p-GaN selective etching, low-temperature Ohmic contact, and Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> passivation have all be realized. The fabricated devices with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</sub> of 16 μm and a simplified epitaxy and device structure, feature a low <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> of 14.8 Ω.mm, a high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> of 2 V, and a high OFF-state breakdown voltage ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BV</i> ) over 1360 V. Further, the nonuniformity of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> across the 6-inch whole wafer is well controlled. Devices also passed the preliminary reliability assessment of high temperature gate bias (HTGB) stress and high temperature reverse bias (HTRB) stress. The high-reliability, high-uniformity, and low-cost p-GaN gate HEMTs on 6-inch sapphire will probably be a strong driven force for the power electronics market in the near future.