Local Oxidation Characteristics of Single Crystal Silicon
Y. Ichida, Y. Morimoto, R. Sato and N. Saito
Utsunomiya University, JP
Keywords: anodization, atomic force microscope, single crystal silicon, process characteristics
Recently, the surface modification with an atomic force microscope (AFM) has attracted special interest as one of the surface processing techniques in a nanometer scale and investigated vigorously . The nanometer-scale scratching (nanoscratching) that removes a material in a nanometer scale is the representative example . Also, the generation of nanometer scale oxide by utilizing electrochemical or tribochemical reactions on the surface has been made a attempt, it was reported that the oxide was possible an application as a mask in the etching [3,4]. We take note of electrochemical local oxidation processing with the AFM as one of the surface processing techniques.
In this study, in order to investigate and discuss the processing characteristics, a series of local oxidation processing experiments on the polished Si (100) surface have been conducted by using the AFM with a silicon tip coated with Pt.
In the spot processing, the influence of the bias voltage, processing time and processing force on the height and diameter of circular oxide is indicated. Although oxidation doesn’t generate in low bias voltage, the height of oxide increases linearly with an increase of the bias voltage in the range over threshold voltage. Also, the height and diameter of oxide increase with an increase of the processing time and processing force. The influence of the processing conditions is larger for a variation of height. In the line processing, the influence of the processing conditions on the height, width and surface roughness of generated oxide is clarified. The height and width of oxide decrease with an increase of the processing speed. The influence of the processing speed is larger for a variation of width. Also, the roughness of the oxide surface is about 0.25 nm in spite of the processing speed. Furthermore, in the crisscross processing, the differences of the oxide generation behavior between the silicon surface and the oxide surface that was already generated are shown.
These results are very useful in the surface modification of micro/nanometer-scale and suggest that the complicated surface modifications are possible by means of combination with nanoscratching.
NSTI Nanotech 2003 Conference Technical Program Abstract