Near-field scanning optical nanolithography using amorphous silicon photoresists

Near-field scanning optical microscopy (NSOM) patterning of hydrogenated amorphous silicon (a-Si:H) has been explored. Our sample preparation technique produces films that are stable over several days. The etching process used is highly selective, allowing the unexposed aSi:H to be completely removed while patterns with line heights equal to the original film thickness remain in exposed regions. We are able to generate patterns with and without the use of light. We have found that the probe dither amplitude greatly affects the linewidth and height of patterns generated without light. We also find that the exposure required for the NSOM to optically generate patterns agrees with threshold dosages determined by far-field exposure studies. Feature sizes of approximately 100 nm, comparable to the probe diameter, were obtained. (C) 1999 American Institute of Physics. [S0003-6951(99)04001-2].