Measurement of Thermal Field Temperature Distribution Inside Reaction Chamber for Epitaxial Growth of Silicon Carbide Layer

Silicon carbide (SiC) has been widely utilized in semiconductor industry for the development of high power electrical devices. Using chemical vapor deposition (CVD) to grow a thin epitaxial layer onto SiC substrate surface with orderly lattice arrangement, good surface morphology and low doping concentration is required. During epitaxial growth, the high reaction temperature and its distribution are generally difficult to measure and will affect the properties of epitaxial growth layer. This study presents a thermal-field testing method based on process temperature control rings (PTCRs) to measure the high temperature distribution inside the epitaxial growth reaction chamber, and to study the effects of reaction chamber structure and epitaxial growth parameters on the quality of epitaxial layer. The measurement accuracy of PTCRs was characterized using silicon melting experiments and the measuring principle of PTCRs was presented. The thermal field of the reaction chamber was then numerically simulated and compared with experimental results. The experiment results exhibit a temperature gradient of less than 0.4 °C/mm on surface, indicating good temperature uniformity. Epitaxial growth is an essential process in the fabrication of SiC devices, as it enables the production of layers with precise doping density and thickness. The SiC epitaxial growth experiments were conducted to study the effects of gas flow ratio and doping flow ratio of three inlet flow channels on the thickness and doping concentration distributions. The results demonstrated that the non-uniformity of thickness and doping concentration of epitaxial layer was below 1.5 % and 4.0 %, respectively.