Roughness transitions of diamond(100) induced by hydrogen-plasma treatment

rms

(PFM), with no obvious anisotropic structures at the surface. After exposure of the B-doped diamond(100) to the H-plasma, the roughness increases dramatically, and pronounced anisotropic structures appear, these being closely aligned with the crystallographic axis’ and planes. An exposure for 3 minutes to the plasma leads to an increase of the roughness to 2–4 nm_rms (STM), and a ‘brick-wall’ pattern appears, formed by weak cusps running along <110>. Very frequently, the cusps are replaced by ‘negative’ pyramids that are bordered by {11X} facets. After an exposure of an additional 5 minutes, the surface roughness of the B-doped samples increases further to 20–40 nm_rms (STM), and frequently exhibits a regular pattern with structures at a characteristic length scale of about 100 nm. Those structures are aligned approximately with <110> and they are faceted with faces of approximately {XX1}. These results will be discussed in terms of strain relaxation, similar to the surface roughening observed on SiGe/Si and anisotropic etching.