Method of manufacturing a semiconductor device having a buried region with higher impurity concentration

Abstract

Since the PN junction of a photodiode is formed of a silicon substrate having a low impurity concentration and an epitaxial layer, the width of the depletion layer in the PN junction is formed wider, the parasitic capacitance by the junction capacitance is lowered, and the diffusion length of the silicon substrate is formed longer. Besides, a buried layer containing a high impurity concentration is formed by a high energy ion implantation method in such a depth that the buried layer cannot be depleted by a reverse voltage applied to the PN junction, which is served as a region to lead out the anode, which accordingly results in a low parasitic resistance at the anode. Thereby, the invention provides a semiconductor device including a photodetector and a method of manufacturing the same that achieves a high photoelectric conversion sensitivity and an excellent frequency characteristic at the same time.

Dependencies are inferred from the claim text.