Thermodynamics of Ion-Cutting of β-Ga₂O₃ and Wafer-Scale Heterogeneous Integration of a β-Ga₂O₃ Thin Film onto a Highly Thermal Conductive SiC Substrate

Abstract

Heterogeneous integration of a β-Ga2O3 thin film with a highly thermal conductive substrate by the ion-cutting process is an intelligent technology to overcome the poor-nature thermal conductivity of β-Ga2O3 and to unleash the full potential of β-Ga2O3 in the field of power electronics. Understanding the basic mechanism of the implantation-induced exfoliation behavior of β-Ga2O3 is vital for better application of the ion-cutting technology. In this work, the thermodynamics of β-Ga2O3 surface blistering induced by H implantation was investigated via an in situ temperature-controlled microscopy stage. A large implantation fluence of H was needed for the ion-cutting of β-Ga2O3 because of the large activation energy (2.28 eV) and low utilization ratio of the implanted H ions (∼9%). A continuous micro-crack, which was essential for the exfoliation of the β-Ga2O3 thin film, was observed via a cross-sectional transmission electron microscope. A 2 in. β-Ga2O3 thin film was successfully transferred onto a 4-in. 4H-SiC substrate via the ion-cutting technique. The transferred β-Ga2O3 thin film exhibited great crystalline quality after a CMP and post-annealing process at 900 °C.