ULTRAVIOLET SENSOR AND METHOD OF MANUFACTURING ULTRAVIOLET SENSOR

• US 20090184254A1
• Filed: 12/24/2008
• Published: 07/23/2009
• Est. Priority Date: 01/22/2008
• Status: Abandoned Application

• Current Assignee: Oki Semiconductor Company Limited (ROHM Co., Ltd.)
• Original Assignee: Oki Semiconductor Company Limited (ROHM Co., Ltd.)
• Inventors: MIURA, Noriyuki
• Application Number:
  US12/343,907
• Publication Number:
  US 20090184254A1
• Time in Patent Office: Days
• US Class Current: 250/372
• CPC Class Codes: G01J 1/429 applied to measurement of ultraviolet light using counting tubes G01T
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 31/109 the potential barrier being of the PN heterojunction type

Abstract

An ultraviolet sensor capable of separately detecting amount of ultraviolet irradiation of two wavelength range of a UV-A wave and a UV-B wave is provided. The ultraviolet sensor includes: a pair of photodiodes in which a high concentration P-type diffusion layer formed by diffusing a P-type impurity with a high concentration and a high concentration N-type diffusion layer formed by diffusing an N-type impurity with a high concentration, which are formed in a first silicon semiconductor layer on an insulation layer, are opposed to each other with a low concentration diffusion layer, which is formed in a second silicon semiconductor layer thinner than the first silicon semiconductor layer by diffusing one of the P-type impurity or the N-type impurity with a low concentration, interposed therebetween; an interlayer insulation film which is formed on the first and second silicon semiconductor layers; a filter film which is formed on the interlayer insulation layer of one of the photodiodes and formed of a silicon nitride film transmitting rays of a wavelength range of the UV-A wave or a longer wave; and a sealing layer which covers the interlayer insulation film of the other of the photodiodes and the filter film and transmits rays of the wavelength range of the UV-B wave or a longer wave.

Claims

1. An ultraviolet sensor comprising:

a pair of photodiodes including a high concentration P-type diffusion layer formed by diffusing a P-type impurity and a high concentration N-type diffusion layer formed by diffusing an N-type impurity formed in a first silicon semiconductor layer on an insulation layer that are spaced apart from each other by a low concentration diffusion layer formed in a second silicon semiconductor layer thinner than the first silicon semiconductor layer, where the low concentration diffusion layer comprises one of the P-type impurity and the N-type impurity at a lower concentration than either of the high concentration P-type diffusion layer or the high concentration N-type diffusion layer;

an interlayer insulation film formed over the first and second silicon semiconductor layers;

a filter film formed over the interlayer insulation layer of one of the photodiodes, the filter film transmitting rays having a wavelength of put into a dependent claim nanometers or longer; and

a sealing layer covering at least the interlayer insulation film of the other of the photodiodes the filter film, transmitting rays having a wavelength of put into a dependent claim nanometers or longer.

2. The ultraviolet sensor according to claim 1, wherein the second silicon semiconductor layer has a thickness from 3 nanometers to 36 nanometers.

3. The ultraviolet sensor according to claim 1, wherein the filter film comprises a silicon nitride film formed by a chemical vapor deposition process in which a flow ratio of monosilane to ammonia to nitrogen to argon is 1.0:

7;

3;

1 under the condition of a temperature between 350°

C. to 450°

C. and a pressure between 4.0 Torr to 6.0 Torr.

4. The ultraviolet sensor according to claim 2, wherein the filter film comprises a silicon nitride film formed by a chemical vapor deposition process in which a flow ratio of monosilane to ammonia to nitrogen to argon is 1.0:

7;

3;

1 under the condition of a temperature between 350°

C. to 450°

C. and a pressure between 4.0 Torr to 6.0 Torr.

5. The ultraviolet sensor according to claim 1, wherein the sealing layer comprises a silicon resin.

6. The ultraviolet sensor according to claim 2, wherein the sealing layer comprises a silicon resin.

7. The ultraviolet sensor according to claim 3, wherein the sealing layer comprises a silicon resin.

8. The ultraviolet sensor according claim 4, wherein the sealing layer comprises a silicon resin.

9. The ultraviolet sensor according to claim 5, wherein the sealing layer comprises a silicon resin.