GaN HEMTs on low resistivity Si substrates with thick buffer layers for RF signal amplification and power conversion

We report GaN high-electron-mobility transistors (HEMTs) with a thick (7.7 mu m) 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 similar to 1.6 x 10(8) 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 f(T)/f(MAX) value of 25.1/32.3 GHz and a maximum output power P-OUT of 2.2 W/mm at 4 GHz with a drain voltage V-DS 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 mu m. 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.

Automated summary

This study reports GaN high-electron-mobility transistors (HEMTs) with a thick GaN buffer on a low-resistivity silicon (LRS) substrate. The HEMTs exhibit high performance in both radio-frequency amplification and power conversion, thanks to the low dislocation density and high vertical voltage blocking capability of the thick GaN buffer.