Semiconductor device
A semiconductor device comprises a semiconductor substrate; an element-forming region that includes semiconductor elements formed on the semiconductor substrate; a buried electrode plug formed so as to penetrate through the semiconductor substrate; and a trench-type electrode that is buried in a trench within the semiconductor substrate positioned between the element-forming region and the buried electrode plug.
1. A semiconductor device comprising:
a semiconductor substrate;
an element-forming region including a semiconductor element and a shallow trench isolation region formed on the semiconductor substrate;
a buried electrode plug formed so as to penetrate through the semiconductor substrate; and
a trench-type electrode buried in a trench within the semiconductor substrate, having a depth greater than a depth of the shallow trench isolation region but not penetrating through the semiconductor substrate, and positioned between the element-forming region and the buried electrode plug, wherein the trench-type electrode is insulated from the substrate.
2. The semiconductor device as claimed in claim 1 , wherein the trench is positioned so as to surround the element-forming region.
3. The semiconductor device as claimed in claim 2 , further comprising a plurality of trenches positioned so as to surround the element-forming region.
4. The semiconductor device as claimed in claim 1 , further comprising a plurality of trenches segmentalized from each other and positioned between the element-forming region and the buried electrode plug.
5. The semiconductor device as claimed in claim 1 , wherein the trench is positioned so as to surround the buried electrode plug.
6. The semiconductor device as claimed in claim 1 , wherein the trench comprises:
a first portion deeper than the isolation region; and
a second portion having the same depth as a depth of the isolation region and communicating with the first portion.
7. The semiconductor device as claimed in claim 6 , wherein:
the trench-type electrode is continuously provided in the first and second portions of the trench,
the semiconductor device further comprises a contact plug connected to the trench-type electrode, and positioned in the second portion, and
a potential is applicable to the contact plug.
8. The semiconductor device as claimed in claim 7 , wherein the trench-type electrode positioned in the second portion is shallower than the isolation region.
9. The semiconductor device as claimed in claim 1 , wherein the trench-type electrode is insulated from the substrate by a silicon oxide film.
10. The semiconductor device as claimed in claim 1 , wherein the trench-type electrode comprises tungsten.
11. The semiconductor device as claimed in claim 10 , wherein the trench-type electrode further comprises a titanium nitride film.