DIRECT OBSERVATION OF HYDROGEN ETCHING ANISOTROPY ON DIAMOND SINGLE-CRYSTAL SURFACES

Etching of natural diamonds by atomic hydrogen has been investigated o n C(100), C(110), and C(111) single crystal surfaces. Infrared absorpt ion spectroscopy and low-energy electron diffraction provide direct ev idence for an etching anisotropy at 1100 K. The results indicate that, in the presence of atomic hydrogen, {111}-oriented facet formation ir reversibly occurs on both C(110) and C(100), whereas C(111) remains in tact. The finding has important implications for chemical vapor deposi tion diamond synthesis and H-plasma surface polishing.