Increased thermal conductivity polycrystalline diamond for low-dissipation micromechanical resonators

Abstract

This paper reports an investigation of microcrystalline diamond (MCD) films deposited under different conditions to increase thermal conductivity and therefore mechanical quality factor (Q) in micromechanical resonators. Through a study of different deposition conditions, we demonstrate a three-fold increase in thermal conductivity and quality factor. Quality factor measurements were conducted on double ended tuning fork resonators, showing Q = 241,047 at fn = 246.86 kHz after annealing, the highest Q reported for polycrystalline diamond resonators. We further present a study of the unique microstructure of hot filament chemical vapor deposition (HFCVD) diamond films and relate growth conditions to observed microstructural defects.