Semiconductor photodiode device and manufacturing method thereof

A method of manufacturing a semiconductor photodiode device comprising the steps of:

• forming an opening window with an insulating film above a semiconductor substrate;
• epitaxially growing a first buffer layer containing a material different from that of the semiconductor substrate in a portion thereof and a first semiconductor layer having a lattice constant different from that of the semiconductor substrate continuously in the window selectively and decreasing a crystal defect density in the first semiconductor layer by a heat treatment;
• crystallographically growing the first semiconductor layer in a direction parallel to the surface of the semiconductor substrate thereby forming a plurality of island shape first semiconductor regions;
• forming a first conduction type second buffer layer containing an element identical with that of the first semiconductor layer in a portion thereof by epitaxial growing and allowing adjacent islands each comprising the first semiconductor region to coalesce with each other;
• and
• forming a first conduction type second semiconductor layer by epitaxial growing above the second buffer layer and decreasing a crystal defect density in the second semiconductor layer by a heat treatment.

A method of manufacturing semiconductor photodiode device comprising the steps of:

• forming, above an imaginary substrate having a second insulating film and a third semiconductor layer formed above a semiconductor substrate, a fourth semiconductor layer having a lattice constant different from that of the semiconductor substrate by epitaxial growing;
• selectively oxidizing only the element identical with the element constituting the semiconductor substrate present in the third semiconductor layer and the fourth semiconductor layer to obtain a fifth semiconductor layer;
• crystallographically growing the fifth semiconductor layer in a direction parallel to the surface of the semiconductor substrate thereby forming a plurality of island shape second semiconductor regions;
• forming a first conduction type third buffer layer containing an element identical with that of the fifth semiconductor layer in a portion thereof by epitaxial growing and allowing adjacent islands each comprising the second semiconductor region to coalesce with each other;
• and
• forming a first conduction type sixth semiconductor layer by epitaxial growing above the third buffer layer and decreasing a crystal defect density in the sixth semiconductor layer by a heat treatment.