THE REACTIVITY OF ION-IMPLANTED SIC

Implantation of chromium into single-crystal or polycrystalline alpha -SiC produces a surface amorphous layer for displacement damage greater than about 0. 2 displacements per atom at room temperature. The enhanced chemical reactivity of such specimens was studied by two methods: chemical etching rate and oxidation rate. The etching rate for the amorphous layer was 2. 4-3. 7 times that of the polycrystalline samples and 3. 0-4. 1 times that of the single-crystal samples. Polycrystalline specimens were exposed to flowing oxygen for 1 hr at 1300 degree C, and Rutherford backscattering and the nuclear reaction **1**6O(d,p)**1**7O* were used to determine the amount of oxygen on the surface. The amount of oxygen (and the thickness of oxide) over the amorphous region was 1. 67 times that over the crystalline region. The relative thicknesses of the oxide on the amorphous and crystalline regions were confirmed by measuring the sputtering time required to remove the oxygen signal in an Auger spectrometer.