Microwave Plasma Etching Treatment for Single Crystal Diamond

Etching treatments of the high temperature high pressure (HTHP) and microwave plasma chemical vapor deposition (MPCVD) single crystal diamond using H-2 and H-2/O-2 microwave plasma were investigated in detail. The etching rates (ER) of IIa type HTHP diamond (HTHP IIa), Ib type HPHT diamond (HTHP Ib), and MPCVD (100) surfaces in H-2 and O-2/H-2 = 2% plasma were measured, respectively, at substrate temperatures in the range of 900-1300 degrees C. Activation energies (E-a) of 68.18 +/- 6.40 kcal mol(-1), 48.12 +/- 2.89 kcal mol(-1), and 59.40 +/- 5.48 kcal mol(-1) have been determined for HTHP Ib, MPCVD, and HTHP IIa substrates by the Arrhenius formula. The etching surfaces were characterized by x-ray photoelectron spectroscopy measurements, laser scanning confocal microscopy, and atomic force microscopy. It is shown that the flat-bottom pit morphology evolves with etching time. The morphology and size of point-bottom pits with different plasma etching O-2/H-2 ratios were also investigated.