Scanning tunneling microscopy studies of temperature-dependent etching of diamond (100) by atomic hydrogen

We present a technique for obtaining atomic resolution ultrahigh vacuum sca nning tunneling microscopy images of diamond (100) films, and use this tech nique to study the temperature dependence of the etching of epitaxial diamo nd (100) films by atomic hydrogen. We find that etching by atomic hydrogen is highly temperature dependent, resulting in a rough and pitted surface at T approximate to 200 and 500 degreesC, respectively. At T approximate to 1 000 degreesC etching results in a smooth surface and is highly anisotropic, occurring predominantly in the direction of dimer rows. This observation s upports recent theoretical models that propose anisotropic etching as the m echanism for the growth of smooth diamond (100) films.