Photoelectric conversion device and method for manufacturing the photoelectric conversion device

A photoelectric conversion device comprising:

• a unit cell comprising:
• a first impurity semiconductor layer having one conductivity type;
• a semiconductor layer including a crystalline semiconductor and an amorphous semiconductor;
• and
• a second impurity semiconductor layer having a conductivity type opposite to the conductivity type of the first impurity semiconductor layer,
• wherein the first impurity semiconductor layer, the semiconductor layer, and the second impurity semiconductor layer are stacked in this order,
• wherein a proportion of the crystalline semiconductor on the first impurity semiconductor layer side of the semiconductor layer is larger than a proportion of the amorphous semiconductor on the first impurity semiconductor layer side of the semiconductor layer,
• wherein a proportion of the amorphous semiconductor on the second impurity semiconductor layer side of the semiconductor layer is larger than a proportion of the crystalline semiconductor on the second impurity semiconductor layer side of the semiconductor layer, and
• wherein the semiconductor layer includes a radial crystal and a crystal having a needle-like growing end in the amorphous semiconductor on the second impurity semiconductor layer side.

A method for manufacturing a photoelectric conversion device, comprising the steps of:

• forming a first electrode over a substrate;
• forming a first impurity semiconductor layer having one conductivity type over the first electrode;
• forming a semiconductor layer over the first impurity semiconductor layer, the step of forming the semiconductor layer comprising the steps of:
• forming a first semiconductor region by introducing a semiconductor source gas and a dilution gas to a reaction chamber with a mixture ratio that allows formation of a microcrystalline semiconductor, generating plasma, and performing deposition over the first impurity semiconductor layer;
• forming a semiconductor particle over the first semiconductor region;
• and
• forming a second semiconductor region over the first semiconductor region and the semiconductor particle by introducing a semiconductor source gas and a dilution gas to a reaction chamber with a mixture ratio that allows formation of a microcrystalline semiconductor at an initial stage of deposition, generating plasma, and performing deposition while a flow ratio of the semiconductor source gas to the dilution gas which are introduced to the reaction chamber is increased gradually or in a stepwise manner so that the semiconductor source gas and the dilution gas are introduced to the reaction chamber with a mixture ratio that allows formation of an amorphous semiconductor at a later stage of deposition;
• forming a second impurity semiconductor layer having a conductivity type opposite to the conductivity type of the first impurity semiconductor layer over the semiconductor layer;
• and
• forming a second electrode over the second impurity semiconductor layer,
• wherein a proportion of a crystalline semiconductor in the first semiconductor region is larger than a proportion of an amorphous semiconductor in the first semiconductor region, and
• wherein a proportion of an amorphous semiconductor in the second semiconductor region is larger than a proportion of a crystalline semiconductor in the second semiconductor region.