Semiconductor device with trench-implemented poly diodes
In a general aspect, a semiconductor device can include a semiconductor substrate, a trench formed in the semiconductor substrate and a first dielectric layer lining the trench. The semiconductor device can further include a first semiconductor material disposed in a lower portion of the trench. The first dielectric layer being can be disposed between the semiconductor substrate and the first semiconductor material. The semiconductor device can also include a second dielectric layer disposed on the first semiconductor material and a second semiconductor material disposed in an upper portion of the trench. The first dielectric layer can be disposed between the semiconductor substrate and the second semiconductor material. The second dielectric layer can be disposed between the first semiconductor material and the second semiconductor material. The semiconductor device can also include at least one of a diode or a resistor defined in the second semiconductor material.
1 . A semiconductor device comprising:
a semiconductor substrate;
a trench formed in the semiconductor substrate;
a first dielectric layer lining the trench;
a first semiconductor material disposed in a lower portion of the trench, the first dielectric layer being disposed between the semiconductor substrate and the first semiconductor material;
a second dielectric layer disposed on the first semiconductor material; and
a second semiconductor material disposed in an upper portion of the trench and excluded from the lower portion of the trench, the second semiconductor material including a plurality of diodes and a gate electrode, the second dielectric layer being disposed between the first semiconductor material and the second semiconductor material.
2 . The semiconductor device of claim 1 , further comprising a metal-oxide-semiconductor field-effect transistor (MOSFET) disposed in the semiconductor substrate, wherein:
the first semiconductor material is electrically coupled with a body region and a source terminal of the MOSFET; and
the first semiconductor material is disposed between a drain region of the MOSFET and the second semiconductor material.
3 . The semiconductor device of claim 2 , wherein the MOSFET is an n-channel MOSFET, the semiconductor device further comprising a p-type well region disposed in the semiconductor substrate adjacent to the trench, the p-type well region being electrically coupled with the body region and the source terminal of the MOSFET and the first semiconductor material.
4 . The semiconductor device of claim 3 , wherein the p-type well region and the body region of the MOSFET are a same well region.
5 . The semiconductor device of claim 3 , wherein the p-type well region is electrically coupled with the body region and the source terminal of the MOSFET via a metal contact that is proximate to the trench.
6 . The semiconductor device of claim 2 , wherein the plurality of diodes is electrically coupled between a gate terminal of the MOSFET and the source terminal of the MOSFET.
7 . The semiconductor device of claim 2 , wherein the first semiconductor material is electrically coupled with the body region and the source terminal of the MOSFET via a metal contact that is proximate to the plurality of diodes.
8 . The semiconductor device of claim 1 , wherein:
the first semiconductor material is first polysilicon material; and
the second semiconductor material is second polysilicon material.
9 . The semiconductor device of claim 1 , wherein the plurality of diodes includes a first diode and a second diode, the first diode and the second diode having a shared anode.
10 . The semiconductor device of claim 1 , wherein the plurality of diodes includes a first diode and a second diode, an anode of the first diode being electrically coupled with a cathode of the second diode.
11 . The semiconductor device of claim 1 , wherein the first dielectric layer is a shield dielectric layer.
12 . The semiconductor device of claim 1 , wherein each of the plurality of diodes is disposed at a same depth in the trench.
13 . The semiconductor device of claim 1 , wherein the second semiconductor material is a polysilicon electrode, and wherein a first portion of the polysilicon electrode includes the plurality of diodes and wherein a second portion of the polysilicon electrode includes the gate electrode.
14 . The semiconductor device of claim 1 , wherein the lower portion of the trench is free of diodes.
15 . A semiconductor device comprising:
a semiconductor substrate;
a first trench formed in the semiconductor substrate;
a second trench formed in the semiconductor substrate;
a first dielectric layer lining the first trench and the second trench;
a first semiconductor material disposed in a lower portion of the first trench and a lower portion of the second trench, the first dielectric layer being disposed between the semiconductor substrate and the first semiconductor material in the first trench and in the second trench;
a second dielectric layer disposed on the first semiconductor material in the first trench and in the second trench;
a second semiconductor material disposed in an upper portion of the first trench and in an upper portion of the second trench, the first dielectric layer being disposed between the semiconductor substrate and the second semiconductor material in the first trench and in the second trench, the second dielectric layer being disposed between the first semiconductor material and the second semiconductor material in the first trench and in the second trench, the second semiconductor material being excluded from the lower portion of the first trench and the lower portion of the second trench; and
for each of the first trench and the second trench, the second semiconductor material includes a plurality of diodes and a gate electrode.
16 . The semiconductor device of claim 15 , further comprising a metal-oxide-semiconductor field-effect transistor (MOSFET) disposed in the semiconductor substrate, wherein, for each of the first trench and the second trench:
the first semiconductor material is electrically coupled with a body region and a source terminal of the MOSFET; and
the first semiconductor material is disposed between a drain region of the MOSFET and the second semiconductor material.
17 . The semiconductor device of claim 16 , wherein the MOSFET is an n-channel MOSFET, the semiconductor device further comprising a p-type well region disposed in the semiconductor substrate adjacent to the first trench and adjacent to the second trench, the p-type well region being electrically coupled with the body region and the source terminal of the MOSFET and the first semiconductor material.