The use of thermal effects for increasing the responsivity of pyroelectric detectors

This paper describes a novel method for increasing the responsivity of pyroelectric infrared detectors in voltage mode. Due to a three-dimensional pattern that is etched into the sensitive element lateral heat flux spreading is used to improve the responsivity. The pattern is a matrix of recessed holes that are etched into the thick pyroelektric element. Here, the effect is used, that very thin regions between thicker regions show a faster heating due to incident radiation and, hence, lead to an additional heat flow from this intermediate regions to the sensitive element. The analysis allows the description of the thermal and electrical behaviour of the sensitive element depending on the dimensions of the pattern and the modulation frequency. Also a technology is presented that allows the fabrication of such a matrix with accurate sidewalls of the recessed holes.