Deep trench super switch device
View Patent ↗A deep trench super switch device has a plurality of trenches, each of the trenches containing a gate electrode polysilicon layer on top of a plurality of stacked conductive floating polysilicon layers, the remainder of each of the trenches being filled with a nonconductive material.
1. A deep trench super switch device comprising:
a drain electrode;
a body formed on the drain electrode of a first conductivity type;
an epitaxial layer of a first conductivity type formed on the body of the first conductivity type;
a plurality of trenches etched into the epitaxial layer, each of the plurality of trenches containing a stack of conductive floating polysilicon layers, a gate electrode on top of the stack of conductive floating polysilicon layers, and a nonconductive material surrounding each of the gate electrode and the conductive polysilicon layers;
a plurality of channel regions of a second conductivity type, each of the channel regions being formed on the epitaxial layer and between two opposing trenches and opposite a respective gate electrode in each of said opposing trenches;
a plurality of source regions of the first conductivity type, each of the source regions being formed in one of the channel regions; and
a plurality of source contacts, each of the source contacts contacting one of the source regions and one of the channel regions.
2. The deep trench super switch device of claim 1 , wherein the plurality of trenches are arranged parallel to one another.
3. The deep trench super switch device of claim 1 , wherein the plurality of trenches extend for the entire depth of the epitaxial layer.
4. The deep trench super switch device of claim 1 , wherein the nonconductive material is silicon dioxide.
5. The deep trench super switch device of claim 1 , wherein the plurality of trenches do not extend for the entire depth of the epitaxial layer.
6. The deep trench super switch device of claim 1 , wherein the gate electrode is a conductive polysilicon layer.
7. The deep trench super switch device of claim 1 , wherein the stack of conductive floating polysilicon layers and the gate electrode have the same cross sectional area.
8. The deep trench super switch device of claim 1 , wherein adjacent trenches have corresponding gate electrodes which are biased to a gate voltage.