Manufacturing method of semiconductor device
First Claim
1. A method of manufacturing a semiconductor device comprising:
- forming a second conductivity type region in a semiconductor substrate having a principal surface of a first conductivity type by implanting impurities of a second conductivity type two or more times;
forming a first conductivity type region inside the island of said second conductivity type region, said first conductivity type region having a higher impurity concentration than said semiconductor substrate;
forming a trench in a depth direction of said semiconductor substrate by anisotropic etching;
forming a sacrificed oxide film on an inner wall surface of the trench by thermal oxidation;
removing said sacrificed oxide film;
forming an insulation film in an interior of said trench;
filling said trench formed said insulation film with a polycrystalline silicon film;
forming a plurality of electric field alleviating regions by introducing impurities of the second conductivity type in a strip-wise shape so as to enclose a peripheral portion of said second conductivity type region;
forming a plurality of strip-wise highly doped second conductivity type regions each formed inside each of the electric field alleviating regions;
forming a plurality of strip-wise third trenches each formed inside each of the strip-wise second conductivity type regions in a depth direction of said semiconductor substrate by anisotropic etching;
forming a plurality of deeper second conductivity type regions each formed inside each of said third trenches by introducing impurities of the second conductivity type by two or more ion implantation steps;
forming a metal electrode which electrically connects each of said strip-wise second conductivity type region to each of said deeper second conductivity type region; and
forming a protection film at least on a surface of the semiconductor substrate except a region where said second conductivity type region underlies.
0 Assignments
0 Petitions
Accused Products
Abstract
By improving profile of impurity concentration in a channel portion of an FET or an IGBT of a trench gate type, variation of threshold value is lessened, and a destruction caused by current concentration is prevented while suppressing deterioration of cut-off characteristics. An island of a base region of p-type is formed in a semiconductor substrate of n-type by carrying out high acceleration ion implantation twice followed by annealing, so that the impurity concentration profile in a channel portion changes gradually in a depth direction. Accordingly, it is possible to lessen variation of the threshold value and to reduce pinch resistance while at the same time improving sub-threshold voltage coefficient and conductance characteristics.
75 Citations
11 Claims
-
1. A method of manufacturing a semiconductor device comprising:
-
forming a second conductivity type region in a semiconductor substrate having a principal surface of a first conductivity type by implanting impurities of a second conductivity type two or more times; forming a first conductivity type region inside the island of said second conductivity type region, said first conductivity type region having a higher impurity concentration than said semiconductor substrate; forming a trench in a depth direction of said semiconductor substrate by anisotropic etching; forming a sacrificed oxide film on an inner wall surface of the trench by thermal oxidation; removing said sacrificed oxide film; forming an insulation film in an interior of said trench; filling said trench formed said insulation film with a polycrystalline silicon film; forming a plurality of electric field alleviating regions by introducing impurities of the second conductivity type in a strip-wise shape so as to enclose a peripheral portion of said second conductivity type region; forming a plurality of strip-wise highly doped second conductivity type regions each formed inside each of the electric field alleviating regions; forming a plurality of strip-wise third trenches each formed inside each of the strip-wise second conductivity type regions in a depth direction of said semiconductor substrate by anisotropic etching; forming a plurality of deeper second conductivity type regions each formed inside each of said third trenches by introducing impurities of the second conductivity type by two or more ion implantation steps; forming a metal electrode which electrically connects each of said strip-wise second conductivity type region to each of said deeper second conductivity type region; and forming a protection film at least on a surface of the semiconductor substrate except a region where said second conductivity type region underlies. - View Dependent Claims (2, 3, 4, 10)
-
-
5. A method of manufacturing a semiconductor device comprising:
-
forming a second conductivity type region in a semiconductor substrate having a principal surface of a first conductivity type; forming a first conductivity type region inside said second conductivity type region, the first conductivity type region having a higher concentration than said semiconductor substrate; forming a plurality of first trenches in a depth direction of said semiconductor substrate by anisotropic etching; forming a sacrificed oxide film formed on an inner surface wall of each of the first trenches by thermal oxidation; removing said sacrificed oxide film; forming an insulation film in an interior of each of said first wenches; filling each of the first trenches with a polycrystalline silicon film; forming a plurality of second trenches in the second conductivity type region each positioned between an adjacent pair of said plurality of first trenches in parallel with said plurality of first trenches; forming a second conductivity type protrusion region with a junction deeper than a junction of said second conductivity type region by introducing impurities of the second conductivity type from each of the second trenches by two or more ion implantation steps; and forming a metal electrode so as to electrically connect said first conductivity type region with said second conductivity type protrusion region in each of the second trenches; after each of the first trenches is filled wit the polycrystalline silicon film, patterning said polycrystalline silicon film so that the patterned polycrystalline silicon film has a T-shaped cross section with a wider width than an opening of each of the first trenches; forming a highly doped first conductivity type region inside said first conductivity type region at a portion from which said polycrystalline silicon film is removed, said highly doped first conductivity type region having a higher concentration than said first conductivity type region; and forming a highly doped second conductivity type layer region inside said highly doped first conductivity type region at a portion between an adjacent two of said plurality of first trenches. - View Dependent Claims (6, 7, 8)
-
-
9. A method of manufacturing a semiconductor device comprising:
-
forming a second conductivity type region in a semiconductor substrate having a principal surface of a first conductivity type; forming a first conductivity type region inside said second conductivity type region, the first conductivity type region having a higher concentration than said semiconductor substrate; forming a plurality of first trenches in a depth direction of said semiconductor substrate by anisotropic etching; forming a sacrificed oxide film formed on an inner surface wall of each of the first trenches by thermal oxidation; removing said sacrificed oxide film; forming an insulation film in an interior of each of said first trenches; filling each of the first trenches with a polycrystalline silicon film; forming a plurality of second trenches in the second conductivity type region each positioned between an adjacent pair of said plurality of first trenches in parallel with said plurality of first trenches; forming a second conductivity type protrusion region with a junction deeper than a junction of said second conductivity type region by introducing impurities of the second conductivity type from each of the second trenches by two or more ion implantation steps; forming a metal electrode so as to electrically connect said first conductivity type region with said second conductivity type protrusion region in each of the second trenches; forming a plurality of electric field alleviating regions by introducing impurities of the second conductivity type in a strip-wise shape so as to enclose a peripheral portion of said second conductivity type region; forming a plurality of strip-wise highly doped second conductivity type regions each formed inside each of the electric field alleviating regions; forming a plurality of strip-wise third trenches each formed inside each of the strip-wise second conductivity type regions in a depth direction of said semiconductor substrate by anisotropic etching; forming a plurality of deeper second conductivity type regions each formed inside each of said third trenches by introducing impurities of the second conductivity type by two or more ion implantation steps; forming a metal electrode which electrically connects each of said strip-wise second conductivity type region to each of said deeper second conductivity type region; and forming a protection film at least on a surface of the semiconductor substrate except a region where said second conductivity type region underlies. - View Dependent Claims (11)
-
Specification