Semiconductor devices with sealed, unlined trenches and methods of forming same
A semiconductor device includes unlined and sealed trenches and methods for forming the unlined and sealed trenches. More particularly, a superjunction semiconductor device includes unlined, and sealed trenches. The trench has sidewalls formed of the semiconductor material. The trench is sealed with a sealing material such that the trench is air-tight. First and second regions are separated by the trench. The first region may include a superjunction Schottky diode or MOSFET. In an alternative embodiment, a plurality of regions are separated by a plurality of unlined and sealed trenches.
1. A semiconductor device comprising:
a semiconductor material layer having a first region and a second region separated by an unlined trench disposed in the semiconductor material layer, the trench having sidewalls comprised of the semiconductor material, the trench being sealed with a sealing material such that the trench is air-tight;
a first metal contact disposed above and in contact with at least a portion of the first region of the semiconductor material layer proximate to the trench; and
a second metal contact disposed above and in contact with at least a portion of the second region of the semiconductor material layer proximate to the trench,
at least a portion of the sealing material being disposed over the trench and between the first metal contact and the second metal contact.
2. The semiconductor device of claim 1 , wherein the semiconductor material layer comprises epitaxial silicon doped with a dopant of a first conductivity type disposed above a substrate comprising silicon doped with a dopant of the first conductivity type in an amount greater than the epitaxial silicon, and wherein at least one of the first region and the second region comprises a superjunction device.
3. The semiconductor device of claim 2 , wherein the first region comprises an active device region and the second region comprises a termination region.
4. The semiconductor device of claim 3 , wherein the active device region comprises one of a superjunction Schottky diode structure, a field-effect-transistor, and a MOSFET structure.
5. The semiconductor device of claim 1 , wherein the air-tight trench contains a gas comprising at least one selected from inert gases and air.
6. The semiconductor device of claim 5 , wherein the gas has a pressure lower than about standard atmospheric pressure.
7. The semiconductor device of claim 5 , wherein the gas has a moisture content less than or equal to about 5%.
8. The semiconductor device of claim 1 , wherein the sealing material comprises spun-on glass.
9. The semiconductor device of claim 1 , wherein the first region comprises one of a superjunction Schottky diode and a first field-effect-transistor and the second region comprises a matching one of a second superjunction Schottky diode and a second field-effect-transistor.
10. The semiconductor device of claim 1 , wherein the semiconductor material layer further comprises a plurality of additional regions, wherein each additional region is separated from adjacent regions by an additional unlined trench disposed in the semiconductor material layer, each additional trench having sidewalls comprised of the semiconductor material, wherein each additional trench is sealed with a sealing material such that each additional trench is air-tight.