Investigation of nanoscratch processes in semiconductor materials for application to maskless patterning

Features of nanoscratching processes with a diamond 90 degrees cube corner tip in semiconductor materials have been studied with different tip orientations and scratch procedures: constant and linearly increasing normal load during scratching, multi-scratching and the direct analysis of the generated scratch by re-scanning the scratch with a strongly reduced normal load. These scratch functions allowed a detailed investigation of the materials response due to the mechanical deformation process. Elastic material recovery, plastic deformation and material removal contribute to the generation of scratch groove profiles. For low applied normal loads mainly elastic deformation occurs whereas for larger normal loads stick-slip processes with periodic hillocks at the groove bottom and irregular pile-up along the scratch rim dominate the process. From the analysis of the scratch groove profile in Si(100), GaAs(100) and thin InSb films, quantitative values for the elastic deformation, the friction coefficient, stick-slip pattern, material removal and scratch depth as a function of the applied normal load are obtained. With multi-scratching a definite removal pattern with a reproducible scratch depth is obtained. These results can be used to optimise the scratch technique for application to maskless patterning.