The long term reliability of a switched-capacitor relative humidity sensor system

Abstract

A switched-capacitor driving circuit for a solid-state relative humidity sensor has been demonstrated. This CMOS circuit has been characterized using a discrete implementation. The circuit has been layed out and simulated for integration on a single chip. In addition, the long-term reliability of the solid-state sensing device has been investigated. The capacitance-RH characteristics exhibits a drift of +5% after eight weeks of aging at 85 degrees C/85% RH. The linearity of the device decreases after 15 weeks of aging. The device drift is the greatest at low frequencies (12 Hz). The stability is best at higher frequencies. An operating frequency of 100 kHz for best device reliability is recommended.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>