1. A reinforced hollow housing member, comprising:
a tube portion having a relatively constant, polygonal cross-section, a flat inner surface, and a first end and a second end; and
a collar portion, integrally attached to said first end, having a cross-section substantially similar to said tube portion but of increased size and having a concave inner surface and an outer surface comprising a flat chamfered base, angled at about 45 degrees and abutting said tube portion.
2. The reinforced hollow housing member of claim 1, wherein said tube portion and said collar portion define a trailer hitch receiver housing.
3. The reinforced hollow housing member claim 1, wherein said polygonal cross-section is generally a square.
4. The reinforced hollow housing member of claim 1 wherein said polygonal cross-section is a four sided shape with ninety (90) degree corners and said collar portion has four interior corners within said hollow housing at said first end with a radius formed in each of the four corners.
5. The reinforced hollow housing member of claim 4 wherein said polygonal cross-section is generally a square.
6. The reinforced hollow housing member of claim 1 wherein said generally polygonal cross-section extends in an axial direction from said first end to said second end and said collar portion has four interior corners within said hollow housing at said first end with an axially extending radius formed in each of the four corners.
7. The reinforced hollow housing member of claim 1 wherein said generally polygonal cross-section extends in an axial direction from said first end to said second end, and said concave inner surface extends in a direction that is generally perpendicular to said axial direction of said cross-section, and said collar portion has four interior corners within said hollow housing at said first end, each of said corners having a formed radius that extends within said hollow housing in said axial direction to the end of said first end.
8. The reinforced hollow housing member of claim 1 wherein said tube portion has an outer surface; said concave inner surface faces said inner surface of said tube portion and said collar portion has an outer surface that extends outwardly beyond said outer surface of said tube portion and has a generally concave outer surface that generally conforms in shape to said inner concave surface.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is
1. A protection device for semiconductor device comprising:
a semiconductor substrate;
a first conductive type well formed on the surface of said semiconductor substrate;
a shallow trench isolation region formed on the surface of said first conductive type well;
first and second diffusion layers of second conductive type formed on both sides of the shallow trench isolation region so as to sandwich the shallow trench isolation region, said second diffusion layer comprising a bent portion where electric fields concentrate and a breakdown current flows when a voltage which is higher than a predetermine voltage is applied to the second diffusion layer; and
a first conductive type well contact formed on the surface of said first conductive type well and connected to said first diffusion layer.
2. The protection device for semiconductor device according to claim 1, further comprising a second conductive type electric field retrieving region with an impurity concentration lower than that of said second diffusion layer provided on the lower side of said second diffusion layer.
3. The semiconductor protection according to claim 1, further comprising a poly-silicon film which covers the upper portion of said bent portion.
4. The semiconductor protection according to claim 1, wherein said second diffusion layer is connected to a gate electrode of a circuit to be protected.
5. The protection device for semiconductor device according to claim 2, wherein said electric field retrieving region is formed so as to contact with said shallow trench isolation region.
6. The protection device for semiconductor device according to claim 3, wherein the bottom portion of said first diffusion layer is positioned at a depth in the vicinity of the bottom portion of said shallow trench isolation region.
7. The protection device for semiconductor device according to claim 3, wherein the bottom portion of said first diffusion layer is formed at a position deeper than the bottom portion of said shallow trench isolation region.
8. A protection method for semiconductor device using a protection device, said protection device comprising a semiconductor substrate; a first conductive type well formed on the surface of said semiconductor substrate; a shallow trench isolation region formed on the surface of said first conductive type well; first and second diffusion layers of second conductive type formed on both sides of the shallow trench isolation region so as to sandwich the shallow trench isolation region, said second diffusion layer comprising a bent portion; and a first conductive type well contact formed on the surface of said first conductive type well and connected to said first diffusion layer, said protection method comprising the step of:
flowing a breakdown current between said bent portion and said well contact when a voltage which is higher than a predetermine voltage is applied to said second diffusion layer.