Numerical Simulation Of High Frequency Induction Heating CVD Conditions And Growth Of SiC Epitaxial Thin Films

Silicon carbide(SiC)is a third-generation semiconductor material,and its important properties such as band gap width,thermal conductivity,and saturated electron drift speed are superior to those of traditional Si materials,making it used in many extreme environments and becoming a semiconductor field.New research core.Among the preparation methods of SiC,chemical vapor deposition(CVD)method has good controllability and is convenient for research and production.The prepared thin film samples have compact structure,good coverage and less impurities,so it is becoming the mainstream method for preparing thin film materials.Since the whole process involves many process parameters,optimizing and improving the preparation process through the traditional trial-and-error method is a very inefficient research method.Introducing the ideas and methods of simulation into the research process,using software to model the experimental equipment,and then simulating the reaction process,not only helps to shorten the optimization period of process parameters and improve the experimental efficiency,but also can deeply understand the equipment structure and reaction situation..In this paper,referring to the parameters of the equipment and experimental raw materials,the detailed modeling and assignment are carried out,and then the experimental parameters are input,and the temperature field,pressure field,air flow field and other information inside the equipment cavity are obtained by calculating and simulating the experimental process.The distribution of physical parameters of the equipment cavity and the influence of different regions on the experiment were studied,and the region in the cavity suitable for the preparation of SiC films on the 4H-SiC substrate was designed.At the same time,the experimental substrate was placed in the cavity through the temperature cloud map.In different positions,samples with different temperature parameters can be obtained in one experiment,to achieve the purpose of batch preparation of experimental samples.The specific experimental process is to use a high-frequency induction heating chemical vapor deposition system,using SiCl4 as the silicon source and CH4 as the carbon source,to prepare SiC thin films on a 4H-SiC substrate with an off-angle of 4 degrees.By adjusting the deposition temperature,carbon-silicon ratio,hydrogen flow,pressure and other process parameters,the microscopic morphology,crystal preferred orientation,deposition rate,crystallinity and electrical properties of the SiC film were tested,and the specific microstructure and growth of the film were studied.process and film properties.With increasing temperature,the crystalline phase transforms from 4H-SiC at 1773 K to a mixture of 4H-and 3C-SiC,and then to a mixture of 3C-SiC and graphite above 1923 K.The films are mainly(004)-oriented 4H-SiC and(111)-oriented 3C-SiC.