Infrared sensor having a heat sensitive semiconductor portion that detects and absorbs infrared rays

摘要

An infrared sensor includes a substrate, an insulator layer formed on the substrate, and a heat-sensitive semiconductor layer having a temperature dependent electrical resistance with a relatively large temperature coefficient of resistance. In order to improve sensitivity of the heat-sensitive semiconductor layer for detecting infrared rays, high concentration impurity semiconductor regions are positioned on either side of the semiconductor layer to form a semiconductor section. The high concentration impurity semiconductor sections have a higher absorption coefficient of infrared rays than the semiconductor layer. Thus, the semiconductor section itself both detects and absorbs infrared rays with or without providing any heat-absorbing layer. Further, electrodes are connected to each high-concentration impurity layer, which form an ohmic contact therewith.