Study of polycrystalline diamond piezoresistive position sensors for application in cochlear implant probe

摘要

Polycrystalline diamond (poly-C) piezoresistive sensors, with high sensitivity, were fabricated and tested for the purpose of integration with Si-based microsystems. The dependence of piezoresistive gauge factor (GF), from 6 to 70, of poly-C films on firm resistivities and grain sizes was investigated in detail. Two seeding methods, with high (10~(10_ cm~(-2)) and low (10~8 cm~(-2)) seeding density, were used to grow poly-C films with small (0.3 mum) and large (0.8 mum) grains, respectively, on 4 inch oxidized Si wafers. Results show that higher resistivities and larger grain sizes yield higher GF. Poly-C piezoresistive position sensors, with a tested GF of 28 and potential GF of 70, were fabricated and integrated into a Si-based cochlear implant probe for the first time.