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

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 Al4C3 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 mfì-cm.