Integrated bulk-micromachined gyroscope using deep trench isolation technology

A novel single-chip bulk-micromachined integrated gyroscope was designed and fabricated in a compatible CMOS process. Using high aspect ratio (30:1) trench etching technology, deep trench electrical isolation materials refilling, and backside etching technologies, bulk MEMS structures and circuits (a part of preamplifier and temperature sensor) were integrated into a single-crystal silicon wafer. A Z-axis integrated gyroscope has been fabricated using this technology, which is compatible with the standard CMOS process. The integrated gyroscope device is 3.5 mm by 3.5 mm in size and has a 100 μm thick single-crystal silicon proof mass. At atmosphere pressure, the packaged gyroscope exhibited a low noise floor (0.008°/sec/√Hz), large scale factor (3.7 mV/°/sec), small nonlinearity (0.08%), and good excursion stability (40°/hr/√Hz).