ALN AS A DRY-ETCH DURABLE RESIST FOR ELECTRON AND ION-BEAM LITHOGRAPHY

Irradiation with an electron or ion beam has been found to reduce the etching rate of rf-sputtered AlN in alkaline or acidic solutions, which shows that this material acts as a negative-type electron and ion beam resist. It has a good resolution and high dry-etch durability. The performance of this resist was demonstrated by defining a 30-50 nm pattern with a high aspect ratio (> 10) in a Si substrate. Although the sensitivity is much lower than that of conventional polymer resists, we believe this material is well suited for experimental fabrication of nanostructures.