Photoelectric conversion device and manufacturing method thereof
A photoelectric conversion device having a new anti-reflection structure is provided. A photoelectric conversion device includes a first-conductivity-type crystalline semiconductor region that is provided over a conductive layer; a crystalline semiconductor region that is provided over the first-conductivity-type crystalline semiconductor region and has an uneven surface by including a plurality of whiskers including a crystalline semiconductor; and a second-conductivity-type crystalline semiconductor region that covers the uneven surface of the crystalline semiconductor region having the uneven surface, the second conductivity type being opposite to the first conductivity type. In the photoelectric conversion device, a concentration gradient of an impurity element imparting the first conductivity type is formed from the first-conductivity-type crystalline semiconductor region toward the crystalline semiconductor region having the uneven surface.
1. A method for manufacturing a photoelectric conversion device, comprising the steps of:
forming a first crystalline semiconductor region by a first low pressure chemical vapor deposition method using a deposition gas containing silicon and a gas imparting a first conductivity type as a source gas over an electrode;
forming a second crystalline semiconductor region that includes a plurality of whiskers including a crystalline semiconductor by a second low pressure chemical vapor deposition method using a deposition gas containing silicon as a source gas over the first crystalline semiconductor region,
moving an impurity element imparting the first conductivity type from the first crystalline semiconductor region toward the second crystalline semiconductor region during the formation of the second crystalline semiconductor region; and
forming a third crystalline semiconductor region by a third low pressure chemical vapor deposition method using a deposition gas containing silicon and a gas imparting a second conductivity type as a source gas over the second crystalline semiconductor region.
2. The method for manufacturing a photoelectric conversion device according to claim 1 , wherein the first low pressure chemical vapor deposition method, the second low pressure chemical vapor deposition method and the third low pressure chemical vapor deposition method are performed at a temperature higher than 550° C.
3. The method for manufacturing a photoelectric conversion device, according to claim 1 , wherein silicon hydride, silicon fluoride, or silicon chloride is used for the deposition gas containing silicon.
4. The method for manufacturing a photoelectric conversion device, according to claim 1 ,
wherein the first conductivity type is one of p-type and n-type, and
wherein the second conductivity type is the other of the p-type and the n-type.
5. The method for manufacturing a photoelectric conversion device, according to claim 1 ,
wherein the gas imparting the first conductivity type is one of diborane and phosphine, and
wherein the gas imparting the second conductivity type is the other of the diborane and the phosphine.
6. A method for manufacturing a photoelectric conversion device, comprising the steps of:
forming a first crystalline semiconductor region that includes a plurality of whiskers including a crystalline semiconductor by a first low pressure chemical vapor deposition method using a deposition gas containing silicon and a gas imparting a first conductivity type as a source gas over an electrode;
forming a second crystalline semiconductor region by a second low pressure chemical vapor deposition method using a deposition gas containing silicon as a source gas over the first crystalline semiconductor region,
moving an impurity element imparting the first conductivity type from the first crystalline semiconductor region toward the second crystalline semiconductor region during the formation of the second crystalline semiconductor region; and
forming a third crystalline semiconductor region by a third low pressure chemical vapor deposition method using a deposition gas containing silicon and a gas imparting a second conductivity type as a source gas over the second crystalline semiconductor region.
7. The method for manufacturing a photoelectric conversion device according to claim 6 , wherein the first low pressure chemical vapor deposition method, the second low pressure chemical vapor deposition method and the third low pressure chemical vapor deposition method are performed at a temperature higher than 550° C.
8. The method for manufacturing a photoelectric conversion device, according to claim 6 , wherein silicon hydride, silicon fluoride, or silicon chloride is used for the deposition gas containing silicon.
9. The method for manufacturing a photoelectric conversion device, according to claim 6 ,
wherein the first conductivity type is one of p-type and n-type, and
wherein the second conductivity type is the other of the p-type and the n-type.
10. The method for manufacturing a photoelectric conversion device, according to claim 6 ,
wherein the gas imparting the first conductivity type is one of diborane and phosphine, and
wherein the gas imparting the second conductivity type is the other of the diborane and the phosphine.