Silicon based polytetrafluoroethylene electrets: Preparation and corona charging characteristics

In this paper, silicon based planar technology and high performance fluorocarbon polymer polytetrafluoroethylene (PTFE) are combined to achieve PTFE thin film electrets on wafer. The PTFE film is fabricated onto SiO2 substrates and Pt substrates using spin coating and annealing processes, and its electret effect is demonstrated using negative corona charging method. PTFE electrets with different surface morphology exhibit different charge storage capability. Maximally, surface potential of −396 V is achieved on Pt substrates and −361 V is achieved on SiO2 substrates. The average retain rate of surface potential over 240 h is 90.6% for Pt substrates and 76.3% for SiO2 substrates. The proposed method presents the primary step toward integrated electrostatic devices.