Integrated Fabrication Of Silicon-based SiC Single Crystal Thin Films Based On Ion Implantation And Lift-off Method

As a third-generation semiconductor,SiC has great application value in many fields due to its excellent physical properties.SiC is integrated into silicon-based heterogeneity to form silicon carbide on insulator（SiCOI）to meet the needs of device miniaturization.Traditional epitaxy or bonding thinning methods have many defects in the preparation of SiCOI thin films,such as difficulty in accurately controlling the film thickness,complicated process,and long time-consuming.The ion implantation exfoliation method can transfer a uniform thickness and high-quality single-crystal SiC film on the substrate and is no longer limited to 3C-SiC,and has unique advantages in the preparation of 4H-SiCOI film.Based on this,this thesis studies the preparation of SiCOI thin film by ion implantation and exfoliation method and its post-treatment process.A systematic research plan was developed for H⁺ions implantation,plasma activated hydrophilic bonding,exfoliation annealing,Ar⁺ions etching,and vacuum annealing of 4H-SiC.Finally,the problem of debonding during the annealing process was solved,the bonding and exfoliating area and film quality were improved,and post-treatment optimization was performed on the exfoliated SiCOI film to remove its oxide layer and defect layer and improve its crystal quality.The research results of this thesis are as follows:1.The simulation and influence research of SiC H⁺ions implantation.Through the joint simulation of SRIM and TRIM software,the energy,angle,dose,and influence of hydrogen ion implantation on SiC were determined.When the implantation energy is180ke V,the implantation angle is 7°,and the implantation dose is 8×10¹⁶cm^-2,the depth of the maximum implantation concentration obtained by simulation is about 1.065μm.After H⁺ions implantation,the surface RMS roughness of 4H-SiC increases from 0.12nm to 0.43nm,the crystal quality decreases slightly,and the stress on the wafer surface increases,but it still meets the requirements of wafer-level hydrophilic bonding.The temperature of the exfoliation window was determined to be 740±20°C through the bubble test.2.Study on hydrophilic bonding and exfoliating of SiC implanted tablets.Through RCA solution cleaning and plasma activation,the surface hydrophilic angles of SiC implanted wafers and Si substrates were reduced to 4.91%and 6.74%of those before cleaning,respectively,and the surface energy was more than doubled,providing a good surface state for hydrophilic bonding.Pre-annealing of Si substrate can effectively improve the unbonding phenomenon,the bonding area increased from 62.56%before pre-annealing to 97.36%,and the bonding area did not decrease to a large extent after heat treatment.It is determined that the best exfoliation annealing parameter is holding at740℃for 40h,and it is found that there is an oxide layer about 30nm thickness on the surface of the SiCOI film and a defect layer introduced by ion implantation,and the internal SiC of the film still maintains a good single crystal state.3.Study on Ar⁺ions etching and vacuum annealing treatment of SiCOI film.Ar⁺ions etching can effectively remove the oxide layer and defect layer,improve the crystal quality while reducing the roughness,and will not damage the internal SiC.Vacuum annealing can recrystallize SiCOI films,thus improving the crystal quality and uniformity of SiCOI films,but too high vacuum annealing temperature will lead to pits on the surface of SiCOI films caused by the difference of thermal expansion coefficient.