| A polycrystalline silicon, surface micromachined oscillator capable of large amplitudes in ambient atmospheric conditions has been demonstrated. The structure is a 2 degree-of-freedom (2DOF), parallel-plate driven motion amplifier, termed the secondary mass drive oscillator (SMD oscillator). This structure may be suitable for low cost, high reliability microgyroscope applications. This work has concentrated on demonstrating and analyzing two "modes" of operation: the contact and non-contact modes. The non-contact mode was less robust and demonstrated lower amplitudes, however analysis indicated that it was insensitive to strain and damping. The contact mode demonstrated robustness and large amplitudes.;In the non-contact mode, the structure did not contact the drive electrode, and lower electrostatic forces are generated. A lumped parameter mathematical analysis of the non-contact mode was developed. Amplitude frequency response data was measured for two device types. The first was operated around the antiresonant frequency of the 2DOF system and demonstrated peak-to-peak amplitudes of 6 mum in air with an applied voltage of 8.6 volts. The second was operated around the first resonant frequency of the 2DOF system and demonstrated peak-to-peak amplitudes of 16 mum in air with an applied voltage of 8 volts.;In the contact mode, the SMD oscillator contacted the drive electrode plates during each cycle, generating large electrostatic forces. Maximum peak-to-peak amplitudes of 54 mum were obtained by operating the structure in air with an applied voltage of 11 volts. A lumped parameter mathematical analysis of the structure was developed and compared to measured data. |
