Research On SiC-on-Si Composite Substrate Integration Technology

Ga N and SiC have attracted much attention as the future revolutionary compound semiconductor（CS）materials,and the hetero-integration of CSs and Si can solve the problems caused by limits of Si physical properties.While utilizing the mature Si semiconductor process,the outstanding materials of CSs are retained.The challenge of Si-based CSs integration is that lattice domination and thermal mismatch between materials reduce the crystal quality of epitaxial CSs thin films.The problem of material property incompatibility can be avoided by growing the buffer layer.Among the buffer materials,SiC shows great potential due to its high lattice matching and low thermal mismatch compared with Si.The SiC-on-Si composite template can be a substrate to prepare SiC power devices and optoelectronic devices,at the same time,the problem of lattice matching can be avoided for growth of Ga N film.Therefore,it is of great significance to study the integration of SiC-on-Si composite substrates.The method of heteroepitaxial growth of SiC buffer layer on Si is limited by the problem of lattice mismatch.The crystal-ion-slicing technology（CIS）,which was born to prepare silicon-on-insulator（SOI）,can perfectly avoid the influence of that.Based on the background,the integration of SiC-on-Si composite substrate was studied in this thesis.A systematic experimental scheme was established for the bonding process and exfoliating preparation of SiC-on-Si.The bonding quality of SiC-on-Si was improved by plasma activation and optimization of activation bonding parameters,and the improved parameters were used to study the exfoliating preparation of SiC-on-Si composite substrates.SiC-on-Si composite substrates were prepared at relatively low temperature.The main results were as follows:Research on bonding process of SiC-on-Si composite substrate.The samples with high surface activity after plasma activation were used for bonding,and the effect of different plasma treatments on the bonding strength of SiC/Si O₂/Si for different treatment time was studied,and the plasma activation parameters were improved to obtain higher SiC/Si O₂/Si The bonding strength of Si reached 6.68MPa when activated by O₂ for 90s;X-ray photoelectron spectroscopy（XPS）was used to analyze the surface chemical states of SiC and Si O₂/Si before and after activation treatment,which revealed that the mechanism of plasma-activated bonding and explained the difference in bonding strength of SiC-on-Si bonded pairs.Study on ion implantation exfoliation of SiC-on-Si.The simulation study of ion implantation was carried out by using SRIM software,the concentration depth of 1μm was obtained in 180ke V.The blistering results after H⁺implantation into SiC satisfied the description of the Arrhenius formula.Based on the ion implantation simulation and the blistering results,it was confirmed that the bubbles generated by the direct bonding of Si and SiC without Si O₂ layer will affect the integrity of the film;Continuous and complete films were prepared at 765°C on Si O₂/Si substrate.The reasons for film wrinkles were analyzed,and the wrinkles were improved by reducing the temperature to 740°C and720°C.Through the test of the film thickness,the values basically consistent with the simulation results are obtained,and SiC films have a smooth and flat surface.Through the test of the single crystallinity,the films exfoliated at different temperatures showed high single crystal quality.The TEM images of the SiC-on-Si composite structures showed that the surfaces of the SiC film have only a few tens of nanometers of damage caused by ion implantation.And the atoms in SiC were arranged periodically in a single crystal.