Patent ID: 7671391
Filing Date: 2010-03-02
Classification: G01S,H01L,H04N

Abstract:
1. A time-of-flight range-finding sensor for range-finding by reading a signal, which depends on a delay time of repetitive light pluses transmitted from a light source and then reflected by a target object to be measured, the time-of-flight range-finding sensor comprising: a p-type semiconductor substrate having a p-type photodetector layer and a p-type well formed at a surface of the semiconductor substrate so as to encircle the photodetector layer in a plan view, the p-type well having a higher concentration than the semiconductor substrate; an insulator layer formed on the photodetector layer; two conductive photo-gate electrodes provided on the insulator layer above the photodetector layer, adjacently disposed so as to define a gap between the two photo-gate electrodes, and being transparent for a wavelength of a light reflected by the target object; and two MOS transistors formed in the p-type well so as to sandwich the photo-gate electrodes, each of the MOS transistors having an n-type floating diffusion layer serving as a source region, which is disposed at a boundary between the photodetector layer and the p-type well and configured to extract charges from the photodetector layer, wherein a uniform optical path exists along the full-width of the gap.