The formation of structural defects in H-plasma treated (100)- and (111)-oriented p-type Czochralski Si and in [100]-oriented n-type Si was studied by Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The samples were treated either by a 110MHz or 13.56MHz H plasma at 250C for 1h. The distribution of H was studied by nuclear reaction analysis. It was found that, after the H plasma treatment, the surface of Cz Si was structured and the roughness of the surface depended upon the orientation and doping level of the substrate. The defect density increased for (100)-oriented wafers for the higher plasma frequency but for (111)-oriented wafers it was lower, applying the same H plasma frequency. Different defect types were found: stacking faults on {111} planes, dislocations and circular shaped defects exhibiting a strong stress field. The formation of nearly free H molecules (Raman shift of about 4150/cm) was observed by Raman spectroscopy after the plasma hydrogenation. It was found that the H2 molecule concentration depended upon the concentration of structural defects. The H molecules could be formed in both n- and p-type Si, unlike the case of remote plasma hydrogenation.

Substrate Orientation, Doping and Plasma Frequency Dependences of Structural Defect Formation in Hydrogen Plasma Treated Silicon. A.G.Ulyashin, R.Job, W.R.Fahrner, O.Richard, H.Bender, C.Claeys, E.Simoen, D.Grambole: Journal of Physics - Condensed Matter, 2002, 14[48], 13037-45