Optoelectronic applications of MOS capacitors fabricated on high resistivity silicon

Optoelectronic applications of MOS capacitors, fabricated on high resistivity silicon substrate, and operating in non-equilibrium mode under a triangular voltage sweep are analyzed. It is found that those MOS capacitors behave as sensitive optical sensors with direct (without analog-digital conversion) quasi-digital output in the form of a pulse-width-modulated signal, duty of which depends on the light intensity. Capacitor-based optical sensors are promising for automatic control, robotic, and metrological applications.