Heterointegrated Ga <sub>2</sub> O <sub>3</sub> -on-SiC RF MOSFETs With <i>f</i> <sub>T</sub> / <i>f</i> <sub>max</sub> of 47/51 GHz by Ion-Cutting Process
Xinxin Yu, Wenhui Xu, Yibo Wang, Bing Qiao, Rui Shen, Jianjun Zhou, Zhonghui Li, Tiangui You, Zhenghao Shen, Kai Zhang, Fangfang Ren, Dongming Tang, Xin Ou, Genquan Han, Yuechan Kong, Tangsheng Chen, Shulin Gu, Youdou Zheng, Jiandong Ye, Rong Zhang
Abstract
Heterointegrated Ga2O3-on-SiC radio-frequency (RF) MOSFETs with record-high frequency performances were reported. A two-dimensional electron gas like channel with a high electron concentration and decent mobility was formed through the shallow implantation of Si into the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3 (−201) nanomembrane integrated on the highly thermal conductive 4H-SiC substrate through an ion-cutting process. The resultant MOSFET yields a high current density of 661 mA/mm and a transconductance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}_{\text {m}}{)}$ </tex-math></inline-formula> of 57 mS/mm. A record-high current cut-off frequency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{\text {T}}{)}$ </tex-math></inline-formula> of 47 GHz and maximum oscillation frequency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{\text {max}}{)}$ </tex-math></inline-formula> of 51 GHz were achieved with the gate length ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {G}}{)}$ </tex-math></inline-formula> scaled down to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1~\mu \text{m}$ </tex-math></inline-formula> . Furthermore, the device with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {G}}= 0.1\,\,\mu \text{m}$ </tex-math></inline-formula> showcases an output power density of 296 mW/mm and a high power gain of 11 dB at 2 GHz in continue wave (CW) mode. It is attributed to the enhanced gate control, elevated current output, and improved thermal conductivity of the heterointegrated Ga2O3 on SiC by ion-cutting process.