Laser‐Based Fabrication of Piezoresistive Cantilevers Utilizing Pulse Laser Annealing

Abstract Microelectromechanical system (MEMS) sensors based on piezoresistive elements are widely used in various applications due to their high sensitivity and compact size. Traditionally, silicon‐based MEMS devices have been fabricated using lithography‐based processes, with piezoresistive layers formed through thermal diffusion or ion implantation. However, these processes involve complex fabrication workflows. In response, laser fabrication techniques, such as laser micromachining and laser annealing‐based impurity diffusion, have attracted attention. In this study, a laser‐based approach for fabricating a silicon piezoresistive cantilever using nanosecond‐pulse laser annealing is proposed. The proposed process integrates two steps: localized laser annealing for impurity doping and the formation of a partially 3D cantilever structure through laser cutting and etching. All the fabrication steps are performed using a single‐laser processing system, enabling direct‐write patterning and automatic alignment of the piezoresistive layer with the sensor structure without lithography. In this paper, the effectiveness of the proposed method is evaluated through electrical and mechanical characterizations of the fabricated sensor. The fabricated piezoresistive layer exhibits a gauge factor exceeding 15, indicating that the sensor is sufficiently effective for practical use.