Semiconductor device including a bipolar structure
First Claim
1. A semiconductor device comprising a semiconductor body having a pair of major surfaces and a pair of main electrodes being connected to said pair of major surfaces respectively, said semiconductor body including a bipolar structure, wherein:
- said bipolar structure has a first semiconductor layer of first conductivity type, second and third semiconductor layers of second conductivity type, and a fourth semiconductor layer of first conductivity type being successively stacked from first to second ones of said pair of major surfaces, said third semiconductor layer having a thickness L, wherein said fourth layer is separated into portions having centers, said centers being each separated by a predetermined distance;
the concentration of a second conductivity type impurity in said second semiconductor layer is higher than that in said third semiconductor layer; and
said bipolar structure further comprises,a semiconductor region having a shorter carrier lifetime than that in said second semiconductor layer,said semiconductor region is selectively formed to have a distance D from another semiconductor region and a width W along said pair of major surfaces to be at least partially overlapped with or to be adjacent to said second semiconductor layer, anda relative distance value D/L equal to the distance D divided by the thickness L and a relative width W/L equal to the width W divided by the thickness L defining a two-dimensional space, wherein said distance D, said width W, and said thickness L have respective values within a region of the two-dimensional space bounded by, but not containing, a first segment having respective coordinates (0, 0.12) and (0.22, 0.44) and a second segment having respective coordinates (0,0) and (0.22,0), anda combined distance of said distance D and said width W being less than said predetermined distance of respective portions of the fourth semiconductor layer.
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Abstract
A high concentration n-type semiconductor region (21) having a width (W) and a distance (D) of constant ranges is selectively formed to be overlapped with or adjacent to a buffer layer (2). When a thickness (L) of an n-type semiconductor layer (3) is 50 μm and the distance (D) is 3 μm, for example, the width (W) is set in the range of 3 μm to 7 μm. In this case, a saturation voltage (VCE (sat)) and a fall time (tf) are improved best as compared with a conventional device having no high concentration n-type semiconductor region (21). Thus, the saturation voltage (VCE (sat)) and the fall time (tf) are compatibly reduced.
25 Citations
21 Claims
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1. A semiconductor device comprising a semiconductor body having a pair of major surfaces and a pair of main electrodes being connected to said pair of major surfaces respectively, said semiconductor body including a bipolar structure, wherein:
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said bipolar structure has a first semiconductor layer of first conductivity type, second and third semiconductor layers of second conductivity type, and a fourth semiconductor layer of first conductivity type being successively stacked from first to second ones of said pair of major surfaces, said third semiconductor layer having a thickness L, wherein said fourth layer is separated into portions having centers, said centers being each separated by a predetermined distance; the concentration of a second conductivity type impurity in said second semiconductor layer is higher than that in said third semiconductor layer; and said bipolar structure further comprises, a semiconductor region having a shorter carrier lifetime than that in said second semiconductor layer, said semiconductor region is selectively formed to have a distance D from another semiconductor region and a width W along said pair of major surfaces to be at least partially overlapped with or to be adjacent to said second semiconductor layer, and a relative distance value D/L equal to the distance D divided by the thickness L and a relative width W/L equal to the width W divided by the thickness L defining a two-dimensional space, wherein said distance D, said width W, and said thickness L have respective values within a region of the two-dimensional space bounded by, but not containing, a first segment having respective coordinates (0, 0.12) and (0.22, 0.44) and a second segment having respective coordinates (0,0) and (0.22,0), and a combined distance of said distance D and said width W being less than said predetermined distance of respective portions of the fourth semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A semiconductor device comprising a semiconductor body having a pair of major surfaces and a pair of main electrodes being connected to said pair of major surfaces respectively, said semiconductor body including a bipolar structure, wherein:
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said bipolar structure has a first semiconductor layer of first conductivity type, second and third semiconductor layers of second conductivity type, and a fourth semiconductor layer of first conductivity type being successively stacked from first to second ones of said pair of major surfaces, said third semiconductor layer having a thickness L, the concentration of a second conductivity type impurity in said second semiconductor layer is higher than that in said third semiconductor layer, and said bipolar structure further comprises, a semiconductor region having a shorter carrier lifetime than that in said second semiconductor layer, said semiconductor region is selectively formed to have a distance D from another semiconductor region and a width W along said pair of major surfaces to be at least partially overlapped with or to be adjacent to said second semiconductor layer, and a relative distance value D/L equal to the distance D divided by the thickness L and a relative width W/L equal to the width W divided by the thickness L defining a two-dimensional space, wherein said distance D, said width W, and said thickness L have respective values within a region of the two-dimensional space bounded by, but not containing, a first segment having respective coordinates (0, 0.12) and (0.22, 0.44) and a second segment having respective coordinates (0,0) and (0.22,
0),said semiconductor body further comprises a fifth semiconductor layer of second conductivity type being selectively formed in said fourth semiconductor layer, said semiconductor device further comprises; a gate electrode being opposed to a channel region through an insulating film, said channel region being a surface part of said fourth semiconductor layer held between said third and fifth semiconductor layers, a trench is formed which opens to said second one of said pair of major surfaces and penetrates said fourth and fifth semiconductor layers, said channel region is exposed to a side wall of said trench, said insulating film covers an inside wall of said trench, and said gate electrode is buried into said trench on said insulating film. - View Dependent Claims (11, 12, 13, 14)
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15. A semiconductor device comprising:
a semiconductor body having, a pair of major surfaces, a pair of main electrodes being connected to said pair of major surfaces respectively, and a bipolar structure having, a first semiconductor layer of first conductivity type, second and third semiconductor layers of second conductivity type, and a fourth semiconductor layer of first conductivity type being successively stacked from first to second ones of said pair of major surfaces, said third semiconductor layer having a thickness L, wherein the concentration of a second conductivity type impurity in said second semiconductor layer is higher than that in said third semiconductor layer; and said bipolar structure fuirther comprises, a semiconductor region having a shorter carrier lifetime than that in said second semiconductor layer, said semiconductor region is selectively formed to have a distance D from another semiconductor region and a width W along said pair of major surfaces to be at least partially overlapped with or to be adjacent to said second semiconductor layer, and a relative distance value D/L equal to the distance D divided by the thickness L and a relative width W/L equal to the width W divided by the thickness L defining a two-dimensional space, wherein said distance D, said width W, and said thickness L have respective values within a region of the two-dimensional space bounded by, but not containing, a first segment having respective coordinates (0, 0.12) and (0.22, 0.44) and a second segment having respective coordinates (0,0) and (0.22,0). - View Dependent Claims (16, 17, 18, 19, 20, 21)
Specification