Microwave plasma deposition of CVD diamond films for MEMS applications

摘要

Selective diamond deposition was carried out on 3-inch silicon substrates at high power (3500 W) and high pressures (55-60 torr) using a surface micromachining technique to fabricate diamond cantilevers and membranes for MEMS applications. Two seeding methods were explored for depositing diamond on silicon dioxide. A grease seeding procedure gave good results on silicon substrates, but the roughness of the deposited diamond films was unacceptable on a silicon dioxide surface. The ultrasonic seeding procedure yielded a smoother diamond film over silicon dioxide. initial depositions carried out by removing the photoresist resulted in stray/spurious diamond growth in undesired regions. A change was implemented by keeping the photoresist on the seeded substrate and carrying out depositions so that the seeding done on regions covered with photoresist was removed, along with the photoresist, during he hydrogen plasma 'burn off'. This change considerably reduced stray diamond growth resulting in easier fabrication of diamond microstructures.