Solid state imaging device and digital camera

摘要

A difference between sensitivity of one of focus detection pixels to incident light from an upper right oblique direction and sensitivity of the other focus detection pixel to incident light from an upper left oblique direction is eliminated.;An OFB layer 38 and a low concentration layer 39 are formed over a semiconductor substrate 29. A PD 40N that constitutes a normal pixel 30N, a PD 40R that constitutes a first focus detection pixel 30R, and a PD 40L that constitutes a second focus detection pixel 30L are formed in the low concentration layer 39. A high concentration barrier layer 38a positioned below a first photoelectric conversion area 52Ra of the PD 40R and a first photoelectric conversion area 52La of the PD 40L is formed in the OFB layer 38. Shapes of the photoelectric conversion areas of the PDs 40R and 40L become asymmetric due to application of voltage to the semiconductor substrate 29, and sensitivity of the photoelectric conversion area of the PD 40R to the incident light IR from the upper right oblique direction and sensitivity of the photoelectric conversion area of the PD 40L to the incident light IL from the upper left oblique direction increase. Because the OFB layer 38 is formed before formation of parts causing surface unevenness, for example, a transfer electrode, the difference between the sensitivities of the focus detection pixels 30R and 30L caused by influence of the surface unevenness is prevented.

主权项

1. A solid state imaging device comprising:
a semiconductor substrate; an impurity layer formed over the semiconductor substrate; a plurality of pixels arranged in a predetermined pattern over the impurity layer, the pixels having photodiodes for generating signal charge through photoelectric conversion and accumulating the signal charge, the pixels producing an image signal of a subject image formed by an optical system, the pixels including at least a pair of two types of focus detection pixels for producing an image signal for focus detection of the optical system using a phase difference method; and an area control layer formed between the semiconductor substrate and the two types of the focus detection pixels, the area control layer making thickness of one of first and second photoelectric conversion areas less than thickness of the other in the photodiode of each of the two types of the focus detection pixels, the first photoelectric conversion areas of the photodiodes of the two types of the focus detection pixels face toward each other, the second photoelectric conversion area being on opposite side of the first photoelectric conversion area in the each photodiode.