Beaucejour Rossiny, D'Agati Michael, Kalyan Kritank, Olsson Roy H
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 220 S. 33rd St., Philadelphia, PA 19104, USA.
Department of Electrical and Systems Engineering, University of Pennsylvania, 3205 Walnut St., Philadelphia, PA 19104, USA.
Micromachines (Basel). 2022 Jul 24;13(8):1169. doi: 10.3390/mi13081169.
Thin film through-thickness stress gradients produce out-of-plane bending in released microelectromechanical systems (MEMS) structures. We study the stress and stress gradient of AlScN thin films deposited directly on Si. We show that AlScN cantilever structures realized in films with low average film stress have significant out-of-plane bending when the AlScN material is deposited under constant sputtering conditions. We demonstrate a method where the total process gas flow is varied during the deposition to compensate for the native through-thickness stress gradient in sputtered AlScN thin films. This method is utilized to reduce the out-of-plane bending of 200 µm long, 500 nm thick AlScN MEMS cantilevers from greater than 128 µm to less than 3 µm.
薄膜的贯穿厚度应力梯度会在释放的微机电系统（MEMS）结构中产生面外弯曲。我们研究了直接沉积在硅上的AlScN薄膜的应力和应力梯度。我们表明，当在恒定溅射条件下沉积AlScN材料时，在平均薄膜应力较低的薄膜中实现的AlScN悬臂结构会有显著的面外弯曲。我们展示了一种方法，即在沉积过程中改变总工艺气体流量，以补偿溅射AlScN薄膜中固有的贯穿厚度应力梯度。该方法用于将200 µm长、500 nm厚的AlScN MEMS悬臂的面外弯曲从大于128 µm减小到小于3 µm。
