Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a single-crystal semiconductor substrate of a first conductivity type;
• a first insulator film selectively covering a first principal surface of the substrate, the first insulator film having an opening;
• a first semiconductor region of the first conductivity type in contact with the substrate in the opening of the first insulator film;
• a second semiconductor region of a second conductivity type on the first insulator film outside the opening thereof;
• a third semiconductor region of the first conductivity type in the second semiconductor region;
• a second insulator film covering the first semiconductor region, the second semiconductor region, and the third semiconductor region;
• a polycrystalline semiconductor region on the second insulator film;
• a first electrode in contact with both the second semiconductor region and the third semiconductor region;
• a third insulator film between the first electrode and the polycrystalline semiconductor region;
• a fourth semiconductor region of the second conductivity type along a second principal surface of the substrate;
• and
• a second electrode in contact with the fourth semiconductor region.

A semiconductor device comprising:

• a single-crystal semiconductor substrate of a first conductivity type;
• a first insulator film selectively buried under a first principal surface of the substrate;
• a first semiconductor region of a second conductivity type between the first insulator film and the first principal surface;
• a second semiconductor region of a first conductivity type in the first semiconductor region;
• a second insulator film covering a region of the first principal surface other than where the first insulator film is buried;
• a polycrystalline semiconductor region provided on the second insulator film;
• a first electrode in contact with both the first semiconductor region and the second semiconductor region;
• a third insulator film between the first electrode and the polycrystalline semiconductor region;
• a third semiconductor region of the second conductivity type along a second principal surface of the substrate;
• and
• a second electrode in contact with the second semiconductor region.

A method of manufacturing a semiconductor device including the steps of:

• forming a first insulator film and a polycrystalline semiconductor film on a first principal surface of a single crystal semiconductor substrate of the first conductivity type;
• forming a window by removing part of the polycrystalline semiconductor film to expose part of the first insulator film;
• forming a second insulator film covering the polycrystalline semiconductor film and the exposed part of the first insulator film in the window;
• exposing part of the substrate in the window by removing the second insulator film and the first insulator film occupying the window;
• depositing a first conductivity type semiconductor film on the exposed part of the substrate in the window and on the second insulator film;
• forming in the first conductivity type semiconductor film a first semiconductor region of a first conductivity type and a second semiconductor region of the second conductivity type adjacent to the first semiconductor region as a region in contact with the substrate in the window;
• forming in the first conductivity semiconductor film a third semiconductor region of the first conductivity type on the opposite side of the first semiconductor region with the second semiconductor region positioned therebetween;
• depositing a third insulator film on the first semiconductor region, the second semiconductor region, and the third semiconductor region, and forming a contact hole in the third insulator film to expose part of the third semiconductor region and part of the second semiconductor region;
• forming a first electrode in contact with the exposed part of the third semiconductor region and the exposed part of the second semiconductor region through the contact hole;
• grinding a second principal surface of the substrate to form a fourth semiconductor region of the second conductivity along the ground second principal surface;
• and
• forming a second electrode in contact with the fourth semiconductor region.

A method of manufacturing a semiconductor device including the steps of:

• forming a first insulator film on a first principal surface of a single crystal semiconductor substrate of a first conductivity type;
• forming a window by removing part of the first insulator film to expose the substrate;
• depositing a first conductivity type semiconductor film on the first insulator film and the exposed part of the substrate in the window;
• forming a second insulator film and a polycrystalline semiconductor film on the first conductivity type semiconductor film;
• removing part of the polycrystalline semiconductor film so that the polycrystalline semiconductor film remaining forms a first semiconductor region of the first conductivity type as a region in which the first conductivity type semiconductor film is in contact with the substrate in the window;
• forming a second semiconductor region of a second conductivity type in the first conductivity type semiconductor film between the first insulator film and the second insulator film;
• forming a third semiconductor region of the first conductivity type in the second semiconductor region;
• depositing a third insulator film on the polycrystalline semiconductor film, forming a contact hole in the third insulator film to expose part of the third semiconductor region and part of the second semiconductor region, and forming on the third insulator film a first electrode in contact with the exposed part of the third semiconductor region and the exposed part of the second semiconductor region through the contact hole;
• grinding a second principal surface of the substrate to form a fourth semiconductor region of the second conductivity along the ground second principal surface;
• and
• forming a second electrode in contact with the fourth semiconductor region.

A method of manufacturing a semiconductor device including the steps of:

• selectively burying a first insulator film under a first principal surface of a single crystal semiconductor substrate of a first conductivity type;
• forming a second insulator film and a polycrystalline semiconductor film on the first principal surface, and removing part of the polycrystalline semiconductor film and part of the second insulator film, leaving the polycrystalline semiconductor film and the second insulator film remaining over a region of the first principal surface other than a region under which the first insulator film is buried;
• forming a first semiconductor region of a second conductivity type in the substrate between the first insulator film and the first principal surface, and further forming a second semiconductor region of the first conductivity type in the first semiconductor region;
• depositing a third insulator film on the polycrystalline semiconductor film, and forming a contact hole in the third insulator film to expose part of the second semiconductor region and part of the first semiconductor region;
• forming a first electrode in contact with the exposed part of the second semiconductor region and the exposed part of the first semiconductor region through the contact hole;
• grinding a second principal surface of the single crystal semiconductor substrate to form third semiconductor region of the second conductivity along the ground second principal surface;
• and
• forming a second electrode in contact with the third semiconductor region.