We study thermal-piezoresistive cooling in silicon micromechanical resonators at large currents and high temperatures. Crossing a thermal transition region corresponds to a steep reduction in resonance frequency, an abrupt plateauing in the effective quality factor, and a large increase in thermomechanical fluctuations. Comparing measurements with simulations suggests that the second-order temperature coefficients of elasticity of doped silicon are not sufficient to capture the drop in resonance frequency at large currents. Overall, our results show that there are clear thermal limits to cooling a resonant mode using current-controlled thermal-piezoresistive feedback in silicon. [2020-0205]

中文翻译：

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硅微机械谐振器中热压阻冷却的限制

我们研究了大电流和高温下硅微机械谐振器中的热压阻冷却。跨越热转变区域对应于共振频率的急剧下降、有效品质因数的突然稳定以及热机械波动的大幅增加。将测量与模拟进行比较表明，掺杂硅的二阶弹性温度系数不足以捕捉大电流下谐振频率的下降。总的来说，我们的结果表明，在硅中使用电流控制的热压阻反馈冷却谐振模式存在明显的热限制。[2020-0205]