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.

A review of gallium oxide-based power Schottky barrier diodes

“…Xu et al reported the wafer-scale exfoliation of β-Ga 2 O 3 thin films by an ioncutting technique with H implantation and transfer onto 4H-SiC and Si substrates with high thermal conductivity. This avoids causing poor quality of the hetero-epitaxy-grown film due to the large lattice mismatch [141][142][143][144][145]. Compared to bulk Ga 2 O 3 wafer, it demonstrated a fine performance improvement in leakage current and breakdown voltage and better thermal stability.…”

Towards Atomic-scale Smooth β-Ga2O3 Surfaces Manufacturing via Atmospheric Pressure Inductively Coupled Plasma

“…Huang et al showed that the asreceived rough β-Ga 2 O 3 crystal substrate with numerous scratches and pits found on the surface can be polished to the damage-free and smooth surface with the Rq surface roughness of 0.21 nm when using silica sol as slurry during the CMP process 5 . Xu et al also demonstrated that the root-mean-square (RMS) surface roughness of β-Ga 2 O 3 thin film deposited on the SiC substrate can be reduced from 5.43 nm to 0.8 nm after CMP process 7 . On the other hand, Ohira et al proposed that an atomically smooth β-Ga 2 O 3 surface with the uniform step-terrace structures can be obtained after the annealing at 1100 for 3 h 8 .…”

Thermal Transport Properties of β-Ga2O3 Thin Films on Si and SiC Substrates Fabricated by an Ion-Cutting Process

“…The ion-cutting technique is compatible with wafer bonding and ion implantation equipment, and it has been used in the industrial application of SOI wafers, which is currently the most suitable heterogeneous integration technology for mass production of heterogeneous integration β-Ga 2 O 3 wafers. 10,11 In our previous work, the thermal transport properties of Ga 2 O 3 −Al 2 O 3 −SiC (GaOISiC) with an intermediate Al 2 O 3 amorphous layer with a thickness of 20 nm were investigated by using transient thermoreflectance (TTR) measurement. 12 The thermal transport properties in β-Ga integration materials (HIMs) are mainly influenced by the thermal conductivity of β-Ga 2 O 3 thin films (κ GaO ), heterogeneous host substrate, and effective thermal boundary resistance of the interface layer (TBR eff ).…”

“…If the defects and twin problems caused by the lattice/thermal mismatch between β-Ga 2 O 3 and any highly thermally conductive substrate can be overcome, then it will greatly subvert the market of β-Ga 2 O 3 power devices. The ion-cutting technique is compatible with wafer bonding and ion implantation equipment, and it has been used in the industrial application of SOI wafers, which is currently the most suitable heterogeneous integration technology for mass production of heterogeneous integration β-Ga 2 O 3 wafers. , …”