While attempting to fabricate low resistance Ohmic contacts to n-GaN and n-AlGaN, processing setbacks necessitated the development of new procedures within the Semiconductor and Microsystems Fabrication Lab (SMFL) at RIT. Photoresist coating recipes usable on GaN pieces were developed for OiR-620 and LOR-5A photoresists, and GaN was etched for the first time on the LAM4600 reactive ion etcher (RIE). The etch was successful, etched GaN at a rate of 187.2 Å/min, and exhibited selectivity between GaN and hard-baked photoresist comparable to an inductively coupled plasma (ICP) etch of the same chemical makeup. An Ohmic Ti to n-GaN contact was fabricated, but was not optimized for low resistance due to time constraints. These processing solutions will enable future GaN-based projects in the SMFL.
"Process Development Challenges Associated with Gallium Nitride Materials,"
Journal of the Microelectronic Engineering Conference: Vol. 22
, Article 8.
Available at: https://scholarworks.rit.edu/ritamec/vol22/iss1/8