In this paper we measure the evolution of adhesion between two polycrystalline silicon sidewalls of a microelectromechanical adhesion sensor during three million contact cycles. We execute a series of AFM-like contact force measurements with comparable force resolution, but using real MEMS multi-asperity sidewall contacts mimicking conditions in real devices. Adhesion forces are measured with a very high sub-nanonewton resolution using a recently developed optical displacement measurement method. Measurements are performed under well-defined, but different, low relative humidity conditions. We found three regimes in the evolution of the adhesion force. (I) Initial run-in with a large of cycle-to-cycle variability, (II) Stability with low variability, and (III) device-dependent long term drift. The results obtained demonstrate that although a short run-in measurement shows stabilization, this is no guarantee for long-term stable behavior. Devices performing similarly in region II, can drift very differently afterwards. The adhesion force drift during millions of cycles is comparable in magnitude to the adhesion force drift during initial run-in. The boundaries of the drifting adhesion forces are reasonably well described by an empirical model based on random walk statistics. This is useful knowledge when designing polycrystalline silicon MEMS with contacting surfaces.

在本文中，我们测量了三百万次接触周期中微机电粘附传感器的两个多晶硅侧壁之间粘附的演变。我们以类似的力分辨率执行了一系列类似于AFM的接触力测量，但是使用了真实的MEMS多粗糙侧壁接触来模拟实际设备中的条件。使用最近开发的光学位移测量方法以非常高的亚纳米牛顿分辨率测量粘附力。在定义明确但不同的低相对湿度条件下进行测量。我们在粘附力的演变中发现了三种机制。（I）初始磨合具有较大的周期间差异，（II）具有低变异性的稳定性，以及（III）依赖于设备的长期漂移。获得的结果表明，尽管短暂的磨合测量显示稳定，但这不能保证长期的稳定行为。在区域II中性能相似的设备其后漂移可能会非常不同。在数百万个循环中的粘附力漂移在大小上可与初始磨合期间的粘附力漂移相当。通过基于随机游动统计的经验模型可以合理地很好地描述漂移粘附力的边界。当设计具有接触表面的多晶硅MEMS时，这是有用的知识。在数百万个循环中的粘附力漂移在大小上可与初始磨合期间的粘附力漂移相媲美。通过基于随机游动统计的经验模型可以合理地很好地描述漂移粘附力的边界。当设计具有接触表面的多晶硅MEMS时，这是有用的知识。在数百万个循环中的粘附力漂移在大小上可与初始磨合期间的粘附力漂移相媲美。通过基于随机游动统计的经验模型可以合理地很好地描述漂移粘附力的边界。当设计具有接触表面的多晶硅MEMS时，这是有用的知识。