Low-Energy Dissipation Diamond MEMS

Microelectromechanical systems (MEMS) that integrate tiny mechanical devices with electronics on a semiconductor substate have experienced explosive growth over the past decades. MEMS have a range of wide applications from accelerometers and gyroscopes in automotive safety, to precise reference oscillators in consumer electrons to probes in atomic force microscopy and sensors for gravitational wave detection. The quality (Q)-factor is a fundamental parameter of a MEMS resonator that determines the sensitivity, noise level, energy efficiency, and stability of the device. MEMS with low energy dissipation have always been pursued. Despite the brilliant progress of silicon-based MEMS due to the mature technology in counterpart microelectronics, the intrinsic material properties limit the sensitivity and reliability, especially for the applications under extreme conditions. Diamond has emerged as the ideal semiconductor material for low-energy dissipation MEMS with high performance and high reliability, owing to its unparalleled material properties, such as extremely high mechanical strength, superelectrical properties, highest thermal conductivity, and chemical inertness. Diamond resonators are thus expected to exhibit high Q-factors, and high reliability, with low thermomechanical force noise and long coherence rate of mechanical quantum states, not only improving the performance of MEMS devices but also expanding to the quantum domain. Single-crystal diamond (SCD) is desirable to achieve the ultralow energy loss or high Q-factor MEMS resonator due to the nonexistence of grain boundaries and other carbon phases. However, micromachining for SCD is tough and heteroepitaxial growth of SCD on foreign substrates remains quite difficult.