Fabrication of nano-gap accelerometer using photo-assisted electrochemical etching

We propose a novel fabrication method for implementing a high precision capacitive type microaccelerometer with uniform nanometer scale gap and have fabricated a nano-gap accelerometer with 135 nm gap and high aspect ratio (>60:1) using modified photo-assisted electrochemical etching. The characteristics of the etching were observed according to the DC bias, the light intensity, and the pitch. After obtaining the optimum etching conditions, the accelerometer with 135 nm sensing gap was designed and fabricated using a 4 masks process.