Semiconductor photodetecting device and illuminance sensor
View Patent ↗The present invention provides a semiconductor photodetecting device that suppresses sensitivity of a short wavelength component of irradiated light as well as a long wavelength component thereof and has a spectral sensitivity characteristic approximately coincident with a human visibility characteristic, and an illuminance sensor including the semiconductor photodetecting device. The semiconductor photodetecting device has a P-type well region and an N-type well region provided side by side along the surface of a P-type semiconductor substrate, a high-concentration N-type region formed in the neighborhood of the surface of the P-type well region, and a high-concentration P-type region formed in the neighborhood of the surface of the N-type well region. A first photoelectric current which flows through a PN junction formed by the P-type well region and the high-concentration N-type region, and a second photoelectric current obtained by adding a photoelectric current which flows through a PN junction formed by the N-type well region and the P-type semiconductor substrate to a photoelectric current which flows through a PN junction formed by the N-type well region and the high-concentration P-type region are extracted. Predetermined arithmetic processing is performed on the first and second photoelectric currents to obtain an output current.
1. An illuminance sensor, comprising:
a semiconductor photodetecting device formed within a P-type semiconductor substrate, the semiconductor photodetecting device including:
a P-type well region and an N-type well region provided side by side along a surface of the P-type semiconductor substrate;
a high-concentration N-type region formed in the neighborhood of a surface of the P-type well region; and
a high-concentration P-type region formed in the neighborhood of a surface of the N-type well region; and
an arithmetic circuit for extracting a first photoelectric current which flows through a PN junction formed by the P-type well region and the high-concentration N-type region and a second photoelectric current obtained by adding a photoelectric current which flows through a PN junction formed by the N-type well region and the P-type semiconductor substrate to a photoelectric current which flows through a PN junction formed by the N-type well region and the high-concentration P-type region, and providing a current obtained by performing predetermined arithmetic processing on the first and second photoelectric currents, as a detected output.
2. The illuminance sensor according to claim 1 , further comprising:
a light transmissive insulating film provided in the surface of the P-type semiconductor substrate, and
a plurality of metal electrodes respectively connected to the P-type well region, the N-type well region, the high-concentration N-type region and the high-concentration P-type region through the insulating film.
3. The illuminance sensor according to claim 2 , wherein an impurity concentration of the P-type well region is higher than an impurity concentration of the P-type semiconductor substrate.
4. The illuminance sensor according to claim 3 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
5. The illuminance sensor according to claim 2 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
6. The illuminance sensor according to claim 1 , wherein a PN junction formed by the N-type well region and the high-concentration P-type region is formed in a position as viewed from the surface of the P-type semiconductor substrate, shallower than a PN junction formed by the P-type well region and the high-concentration N-type region.
7. The illuminance sensor according to claim 6 , wherein an impurity concentration of the P-type well region is higher than an impurity concentration of the P-type semiconductor substrate.
8. The illuminance sensor according to claim 7 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
9. The illuminance sensor according to claim 6 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
10. The illuminance sensor according to claim 1 , wherein an impurity concentration of the P-type well region is higher than an impurity concentration of the P-type semiconductor substrate.
11. The illuminance sensor according to claim 10 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
12. The illuminance sensor according to claim 1 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
13. The illuminance sensor according to claim 1 , wherein a PN junction formed by the N-type well region and the high-concentration P-type region is formed in a position as viewed from the surface of the P-type semiconductor substrate, shallower than a PN junction formed by the P-type well region and the high-concentration N-type region.
14. The illuminance sensor according to claim 13 , wherein an impurity concentration of the P-type well region is higher than an impurity concentration of the P-type semiconductor substrate.
15. The illuminance sensor according to claim 14 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
16. The illuminance sensor according to claim 13 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
17. The illuminance sensor according to claim 1 , wherein an impurity concentration of the P-type well region is higher than an impurity concentration of the P-type semiconductor substrate.
18. The illuminance sensor according to claim 1 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.
19. The illuminance sensor according to claim 1 , wherein the P-type well region is formed by two ion-implantations different in implantation energy from each other.