MOS device with low injection diode
AssigneeAlpha and Omega Semiconductor Incorporated
InventorsAnup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
Life of this patent
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Abstract
A semiconductor device is formed on a semiconductor substrate. The device includes a drain, an epitaxial layer overlaying the drain, and an active region. The active region includes a body disposed in the epitaxial layer, having a body top surface, a source embedded in the body, extending from the body top surface into the body, a gate trench extending into the epitaxial layer, a gate disposed in the gate trench, an active region contact trench extending through the source and into the body, an active region contact electrode disposed within the active region contact trench, wherein a thin layer of body region separating the active region contact electrode from the drain.
Claims24
A semiconductor device formed on a semiconductor substrate, comprising:
- a drain;
- an epitaxial layer overlaying the drain;
- and an active region comprising:
- a body disposed in the epitaxial layer, having a body top surface;
- a source embedded in the body, extending from the body top surface into the body;
- a gate trench extending into the epitaxial layer;
- a gate disposed in the gate trench;
- an active region contact trench extending through the source and into the body;
- an active region contact electrode disposed within the active region contact
- trench;
- wherein:
- the body includes a thin body layer that separates the active region contact electrode from the drain and that has a dopant concentration that is substantially the same as the rest of the body;
- thickness and dopant concentration of the body layer are such that in a reverse bias mode the layer of body region is substantially depleted, and in a forward bias mode the layer of body region is not depleted;
- wherein a low injection diode is formed below a body/drain junction.
A method of fabricating a semiconductor device, comprising:
- forming a gate trench in an epitaxial layer overlaying a semiconductor substrate;
- depositing gate material in the gate trench;
- forming a body;
- forming a source;
- forming an active region contact trench that extends through the source and into the body, and disposing a contact electrode within the active region contact trench;
- wherein:
- the body includes a thin body layer that separates the active
- region contact electrode from the drain and that has a dopant concentration that is
- substantially the same as the rest of the body;
- thickness and dopant concentration of the body layer are such that in a reverse bias mode the layer of body region is substantially depleted, and in a forward bias mode, the layer of body region is not depleted;
- wherein a low injection diode is formed below a body/drain junction.
Dependencies are inferred from the claim text.