UV Sensor Doped Regions Block Visible Light

The patent extracts the filtering function from a separate multilayer filter component and integrates it directly into the semiconductor substrate through doped regions. The first conductivity type substrate with second conductivity type regions creates built-in electric fields that selectively guide ultra-violet photoelectrons while blocking visible and infrared photoelectrons, eliminating the need for expensive precious metal filters and improving manufacturing yield.

The semiconductor substrate serves multiple functions simultaneously: it acts as both the photoelectric conversion medium and the wavelength-selective filter. The doped regions create electric fields that perform both charge collection and spectral filtering, combining what were previously separate functions into a single integrated structure that reduces manufacturing complexity and cost.

The patent applies different conductivity types and doping densities at different locations within the semiconductor substrate. The first conductivity type substrate has specific doped regions with tailored electrical properties that create localized electric fields. These fields are configured to attract ultra-violet photoelectrons to the collection region while repelling or blocking visible and infrared photoelectrons, achieving wavelength-selective sensing through spatially varying electrical properties.

The built-in electric fields created by the doped regions act as intermediaries that selectively guide different types of photoelectrons. These electric fields mediate the movement of charge carriers by wavelength, directing ultra-violet photoelectrons to the collection electrode while preventing visible and infrared photoelectrons from reaching the sensing region, thus resolving the interference problem.