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 temperature up to 1700 degrees C. The inner cell is surrounded by a highly reflecting heat shield. 6H dan 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 mu m step bunching appears. Unintentionally doped material is n-type and has a doping concentration in the 10(15) cm(-3) range. Intentional N and Al doping could be controlled from 10(16) cm(-3) up to 10(19) and 10(21) cm(-3), respectively. The compensation level is in all cases in the range of 10(14) cm(-3). The Al doping turn-off from a concentration of 2 x 10(19) cm(-3) to 2 x 10(15) cm(-3) over 50 nm has been achieved by using an HCl etch at the interface. The thickness uniformity is within +/-24% for growth at 1250 degrees C, but improved to within +/-6% for growth at 1550 degrees C. From growth behavior at different growth conditions we conclude that the process is mainly diffusion limited.