Growth of step-free surfaces on device-size (0001)SiC mesas

It is believed that atomic-scale surface steps cause defects in single-crys tal films grown heteroepitaxially on SiC substrates. A method is described whereby surface steps can be grown out of existence on arrays of device-siz e mesas on commercial "on-axis" SiC wafers. Step-free mesas with dimensions up to 200 mu m square have been produced on 4H-SiC wafers and up to 50 mu m square on a 6H-SiC wafer. A limiting factor in scaling up the size and yi eld of the step-free mesas is the density of screw dislocations in the SiC wafers. The fundamental significance of this work is that it demonstrates t hat two-dimensional nucleation of SiC can be suppressed while carrying out step-flow growth on (0001)SiC. The application of this method should enable the realization of improved heteroepitaxially-grown SiC and GaN device str uctures. (C) 2000 American Institute of Physics. [S0003-6951(00)02636-X].