Growth and electrical characterization of Al-N Co-doping SiC single crystals

Abstract

The growth of p-type SiC crystals with low resistivities should be investigated due to its application inn-channel Insulated Gate Bipolar Transistor (IGBT) fabrication. In this paper, the growth of 2 inch p-type 4H-SiC single crystals was carried out by conventional physical vapor transport (PVT) method with Al 4 C 3 as Al dopant source. Results showed that the aluminum atoms can be effectively incorporated into SiC crystals and the color of Al-doped 4H-SiCcrystals was blue. With the increase of aluminum content in SiC crystals, the color of Al-doped SiC became darker and eventually opaque. At heavy Al doping condition, the polytype of 4H-SiC was not stable and the grown crystals easily turned to 6H-SiC polytype. In addition, by adopting Al-N co-doping technique, p-type SiC single crystals with stable 4H-SiC polytype were grown. However, due to the difficulty in controlling the release of Al, Al-N co-doped single crystals turned to n-p-n type conduction crystals. Noncontact resistivity measurement showed the minimum resistivity of p-type 4H-SiC wafers was about 4149 mfi-cm.