Fine patterning of electrets for sensors and energy harvesters

Charge patterning on 1.3 μm-wide electret lines has successfully been demonstrated with a voltage of 80 V between charged Si
₃
N
₄
lines and discharged unpatterned underlying SiO
₂
. The fabrication technology and charge patterning methods were developed. A nine-month aging test on open air confirms that there is seemingly no dependence of charge retention time on line width within the 1 mm to 1.3 μm range. Accounting for the decay of surface potential during 9 months of aging, the charge lifetime in 1.3 μm-wide electret lines is about 40 years.