Patent ID: 6521968
Filing Date: 2003-02-18
Classification: G02B,H01L

Abstract:
A back-illuminated-type photodiode that concurrently admits light having a longer wavelength, &lgr;2, and light having a shorter wavelength, &lgr;1, and that detects only the light having a shorter wavelength, &lgr;1, which photodiode comprising:(a) a semiconductor substrate; (b) an absorption layer being: (b1) placed on the semiconductor substrate; (b2) provided with a pn junction in the layer; and (b3) made of a semiconductor material having a bandgap wavelength, &lgr;g, longer than &lgr;1 and shorter than &lgr;2; (c) a cap layer being: (c1) placed in contact with the absorption layer; and (c2) made of a material that absorbs light having the wavelength &lgr;2; (d) a first electrode being: (d1) placed in contact with the bottom surface of the semiconductor substrate; and (d2) provided with an opening for admitting light; and (e) a second electrode being: (e1) placed on the cap layer; and (e2) provided with an opening for allowing light to leave the photodiode.