Low temperature mechanical properties of boron-doped silicon

The audio-frequency mechanical properties of oscillators fabricated from boron-doped single-crystal silicon were measured as a function of temperature. The mechanical properties (Q^-1 and period) are dominated by the boron impurities and cannot be attributed to glassy defects. We also found the higher strain mechanical response of these crystals to be nonlinear below 0.3 K. The strength of this nonlinearity is related to the boron concentration.