1. GaN HEMTs on low resistivity Si substrates with thick buffer layers for RF signal amplification and power conversion.
- Author
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Song, Wenjie, Zhang, Jie, Zheng, Zheyang, Feng, Sirui, Yang, Xuelin, Shen, Bo, and Chen, Kevin J.
- Subjects
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RADIO frequency , *BUFFER layers , *GALLIUM nitride , *MODULATION-doped field-effect transistors , *BREAKDOWN voltage , *LATTICE constants , *DISLOCATION density - Abstract
We report GaN high-electron-mobility transistors (HEMTs) with a thick (7.7 µm) GaN buffer on a Czochralski low resistivity Si (LRS) substrate. The GaN HEMTs exhibit high performance for both radio-frequency (RF) amplification and power conversion. The thick GaN buffer was grown by means of vacancy engineering, delivering a low dislocation density of ∼1.6 × 108 cm−2, contributing to suppressed RF signal coupling to the lossy Si substrate and a high vertical voltage blocking capability. For RF performance, GaN HEMTs with a 650 nm gate exhibit an fT/fMAX value of 25.1/32.3 GHz and a maximum output power POUT of 2.2 W/mm at 4 GHz with a drain voltage VDS of 20 V, which is comparable with the performance of RF GaN HEMTs on a high-resistivity silicon substrate without the existence of the field plate. For power performance, the vertical breakdown voltage of the wafer is 1160 V, and the three-terminal lateral breakdown voltage is 885 V in a GaN HEMT with a gate-to-drain distance of 8 µm. The thick GaN layer on the LRS substrate scheme thus provides a compelling platform for monolithic integration of high-performance RF devices and high-voltage power devices. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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