Nano-oxidation of H-terminated p-Si(100):: Influence of the humidity on growth and surface properties of oxide islands

Nanometer-scale oxide islands were formed on p-Si(100) by use of an atomic-force microscope in ambient air. The islands were investigated using contact and friction mode. Volumes were determined from cross-sectional measurements before and after HF etching. A pronounced influence of the relative humidity (h(r)) of the ambient air on the size and on the friction behavior of the islands was found. A distinct peak of the size distribution was observed at h(r) approximate to 85%. The friction images showed a clear contrast inversion at this humidity value. At lower humidities, the friction between tip and oxide was larger than on H-terminated silicon, at higher humidities, it was lower. A condensation mechanism occurring at the meniscus between the tip and H-terminated silicon surface is suggested, which explains the results. (C) 2001 American Institute of Physics.