Design and Performance of a New Reactor for Vapor Phase Epitaxy of 3C, 6H, and 4H SiC
The design of a new horizontal reactor for vapor phase epitaxy of SiC is presented. The reactor has a graphite inner cell with rectangular cross section to align the gas stream, and it may handle temperatures up to 1700°C. The inner cell is surrounded by a highly reflecting heat shield. 6H and 4H SiC were grown homoepitaxially, and 3C SiC was grown on (111) and (001) oriented Si. The 3C SiC is shown to be epitaxially oriented to the substrate, but with some mosaicity. For 4H and 6H SiC the crystallinity is limited by the substrates, and for layers thicker than 20 μm step bunching appears. Unintentionally doped material is n‐type and has a doping concentration in the 1015 cm−3 range. Intentional N and Al doping could be controlled from 1016 cm−3 up to 1019 and 1021 cm−3, respectively. The compensation level is in all cases in the range of 1014 cm−3. The Al doping turn‐off from a concentration of to over 50 nm has been achieved by using an HCl etch at the interface. The thickness uniformity is within ±24% for growth at 1250°C, but improved to within ±6% for growth at 1550°C. From growth behavior at different growth conditions we conclude that the process is mainly diffusion limited.
Source:IOPscience
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