Abstract: A method for etching an HgCdTe substrate selectively by dry etching. A substrate is selectively etched without damaging the substrate during a simple process in which the higher selectivity of an HgCdTe substrate versus a resist mask is obtainable. Removal of the resist mask after etching is easy. The etching gas contains molecules having a bond of nitrogen and hydrogen and is formed into plasma. An HgCdTe substrate is etched with a resist film as a mask by the plasma gas.

Abstract: A photoelectric transducer having a photocell includes a compound semiconductor substrate in which a photodiode is doped by an impurity of a conductivity type opposite to that of the substrate. An enclosure region is formed by the same doping impurity as the photodiode, surrounding but spaced apart from the photodiode. A gate electrode is formed on a portion of an insulation layer, the latter formed all over the substrate surface, which extends between the photodiode and the enclosure region. The enclosure region is selectively connected, via a contact hole through the insulation layer and a first switch to ground level. The gate electrode is connected via a second switch to a predetermined voltage having the same polarity as the conductivity type of the substrate.