Pressure Dependence of Aluminum Doping in SiC Vapor Phase Epitaxy

摘要

The dependence of the aluminum incorporation on the total pressure in a hot wall vapor phase reactor for SiC homoepitaxial growth has been investigated. It was found that in the doping concentration range from 1·10~(17) cm~(-3) to 1·10~(19) cm~(-3) the incorporated aluminum concentration varies by the factor 3 to 4, when the reactor pressure is changed from 150 mbar to 250 mbar. Lower reactor pressure gives lower aluminum concentration. Periodically changing reactor pressure results in aluminum concentration periodically changing with depth in the epilayer. All results were measured electrically by capacitance-voltage measurements on nickel Schottky contacts. Additional experiments have been performed for n-type nitrogen doped SiC epilayers for comparison. The nitrogen doping concentration was found to be independent of the reactor pressure within the accuracy of the applied C-V measurements and the doping profile analysis method.