Complete surface exfoliation of 4H-SiC by H+- and Si+-coimplantation

Implantation of 4H-SiC with H-1(+) and Si-28(+) ions followed by annealing is shown to result in complete ejection or exfoliation of the implanted lay er. This is in contrast to H+-only implantation where only partial exfoliat ion of the surface can be achieved. The mechanisms of this process and its dependence on implantation conditions are discussed. It is shown that amorp hization of the surface region during Si+ irradiation is a necessary condit ion to produce this effect, and that it depends critically upon the thickne ss of the amorphous layer. Stress, induced by bulk recrystallization of the amorphized layer, acts as an additional driving force for H+ induced exfol iation causing the surface layer to separate completely at a depth near the end-of-range of the H+ ions. The morphologies of the newly exposed surface s are studied by profilometry measurements and atomic force microscopy. (C) 2000 American Institute of Physics. [S0003- 6951(00)03722-0].