First Demonstration of Waferscale Heterogeneous Integration of Ga<inf>2</inf>O<inf>3</inf> MOSFETs on SiC and Si Substrates by Ion-Cutting Process

Abstract

We for the first time demonstrate the heterogeneous integration of 2-inch β-Ga2O3 thin films onto the 4H-SiC and Si (001) substrates by ion-cutting process, as well as the fabrication of high-performance β-Ga2O3 MOSFETs on the heterogeneous wafers. 2-inch single-crystalline β-Ga2O3 thin film with a wafer-level thickness non-uniformity below ±1.8% is transferred onto Si and SiC substrates. Three high-quality heterogeneous wafers, the Ga2O3-on-SiC (GaOSiC), Ga2O3-Al2O3-SiC (GaOISiC), and Ga2O3-Al2O3-Si (GaOISi) are fabricated, which have surface RMS roughness below 0.5 nm and the FWHM of XRD rocking curve of 130 arcsec. By varying the channel thickness, both enhancement- and depletion-mode MOSFETs are realized on GaOSiC wafer. As the ambient temperature increases from 300 K to 500 K, little degradation is observed in the on-resistance, forward saturation current, reverse leakage current and breakdown voltage (Vbr) of the fabricated Ga2O3 MOSFETs. A device Vbr above 600 V is achieved at 500 K with a weak dependence on temperature. These results show a significantly improved device thermal stability compared to the reported Ga2O3-on-Ga2O3 devices. The technology demonstrated in this work is promising to overcome the fundamental thermal limitation of Ga2O3 electronics for high-power applications.