Title :
Stabilization of positive charge in SiO/sub 2//Si/sub 3/N/sub 4/ electrets
Author :
Leonov, V. ; Fiorini, P. ; Van Hoof, C.
Author_Institution :
Interuniv. Microelectron. Center, Leuven
Abstract :
The stability of charge storage in electrets is a key parameter for their use in practical devices. For this purpose a new charging procedure for SiO2/Si3N4 thin film electret on a silicon carrier has been developed. It combines a heat-treatment at 450degC with a hexamethyldisilazane treatment before charging of the electret. The retention of a positive charge and the stability of its spatial trapping are investigated. The optimized technological parameters provide a lifetime of the charge on open air of about 200 years. No spatial charge retrapping has been observed after fabrication of the electret. A set of experiments has been carried out to characterize the properties of the charged electrets and to stabilize the charge retention using heat treatment at temperatures up to 450degC after charging, which is important for their packaging at elevated temperatures
Keywords :
carrier lifetime; dielectric thin films; electrets; heat treatment; silicon compounds; 450 C; SiO2-Si3N4; charge storage; heat-treatment; hexamethyldisilazane treatment; positive charge; silicon carrier; spatial charge retrapping; spatial trapping; thin film electret; Electrets; Fabrication; Heat treatment; Microelectronics; Micromechanical devices; Semiconductor films; Silicon; Stability; Temperature; Wireless sensor networks;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
DOI :
10.1109/TDEI.2006.247831