Wafer-scale single-crystalline β-Ga2O3 thin film on SiC substrate by ion-cutting technique with hydrophilic wafer bonding at elevated temperatures

Abstract

Heterogeneous integration of β-Ga 2 O 3 on a highly thermal conductive SiC substrate is an efficient solution to solve its bottleneck of thermal dissipation for highpower electronics. In this work, a 2-inch high-quality (201) β-Ga 2 O 3 single-crystalline film was transferred to the 4H-SiC substrate via the ion-cutting technique with hydrophilic bonding at elevated temperatures. The evolution process of the surface blistering on the hydrogen-implanted β-Ga 2 O 3 together with the internal pressure in blisters were investigated systematically to understand the physical mechanisms of the ion-cutting of β-Ga 2 O 3 thin film. As suggested by the finite element simulation, the hydrophilic bonding was carried out at an elevated bonding temperature of 96°C to prevent the debonding of β-Ga 2 O 3 /4H-SiC during the ioncutting process via reducing the thermal stress. The astransferred β-Ga 2 O 3 thin film exhibited a narrow full width at half maximum of the X-ray diffraction of 79.2 arcsec, and an extremely smooth surface with a root-mean-square roughness of 0.1 nm was achieved after chemical mechanical polishing. It is expected that the β-Ga 2 O 3 /4H-SiC heterogeneous integration material obtained by the ion-cutting technique with hydrophilic bonding at elevated temperatures will serve as a practical platform for high-performance β-Ga 2 O 3 power devices.

Research on bubble-free Si/SiC hydrophilic bonding approach for high-quality Si-on-SiC fabrication

“…Wafer bonding is a promising approach to avoid the problem of lattice constant mismatch between different materials. 11,12) Recently, many novel heterostructures, such as β-Ga 2 O 3 -on-SiC, 13) have been fabricated by wafer bonding technique. Actually, the technique of fabricating Si-on-SiC by employing wafer bonding has been proposed by many researchers.…”

Heterogeneous integration technology for the thermal management of Ga2O3 power devices

“…The sliced thin film is then transferred onto a handle wafer via a wafer bonding pro-cess, as shown in Fig. 1 [4] . The exfoliated wafer-scale thin film maintains good crystallization quality similar to the donor bulk, and the remaining bulk can be recycled to lower the process cost.…”

“…The utilization of these substrates with high thermal conductivity and good insulating properties has led to improved temperature-dependent ON-and OFF-state current performance in heterogeneous Ga 2 O 3 MOS-FETs compared to bulk devices. Experimental demonstra- [4] . Copyright 2021, with permission from IEEE.…”

“…(Color online) The process flow for transferring β-Ga 2 O 3 thin film onto SiC (or Si) by ion-cutting. Reprinted from Xu et al[4] . Copyright 2021, with permission from IEEE.…”