Method of manufacturing semiconductor device and semiconductor device
AssigneeShindengen Electric Manutauturing Co., Ltd.
InventorKinya OHTANI
Life of this patent
Estimating the term…
Abstract
A method of manufacturing a semiconductor device includes in this order: a semiconductor base body preparing step; a first trench forming step; a first insulation film forming step of forming a first insulation film; a gate insulation film forming step; a gate electrode forming step; a second trench forming step of forming a second trench in the inside of a first trench by removing a center portion of the first insulation film; a second insulation film forming step of forming a second insulation film in the inside of the second trench under a condition that a gap remain in the inside of the second trench; a shield electrode forming step of forming a shield electrode in the inside of the gap; and a source electrode forming step of forming a source electrode.
Claims15
A method of manufacturing a semiconductor device having a shield gate structure where a gate electrode and a shield electrode are separated from each other in an in-plane direction, the method comprising in the following order:
- a semiconductor base body preparing step of preparing a semiconductor base body having a first conductive-type first semiconductor layer and a first conductive-type second semiconductor layer having lower concentration than the first semiconductor layer;
- a first trench forming step of forming a predetermined first trench on the second semiconductor layer;
- a first insulation film forming step of forming a first insulation film such that the first insulation film is filled in a lower portion of the first trench;
- a gate insulation film forming step of forming a gate insulation film on a side wall of an upper portion of the first trench;
- a gate electrode forming step of forming the gate electrode made of polysilicon with the gate insulation film interposed between the upper portion of the first trench and the gate electrode;
- a second trench forming step of forming a second trench in the inside of the first trench by removing a center portion of the first insulation film by etching;
- a second insulation film forming step of forming a second insulation film in at least the inside of the second trench under a condition that a gap remain in the inside of the second trench;
- a shield electrode forming step of forming the shield electrode in the inside of the gap;
- and
- a source electrode forming step of forming a source electrode such that the source electrode is electrically connected to the shield electrode.
A semiconductor device which includes a shield gate structure where a gate electrode and a shield electrode are separated from each other in an in-plane direction, the semiconductor device comprising:
- a semiconductor base body having a first conductive-type first semiconductor layer and a first conductive-type second semiconductor layer having lower concentration than the first semiconductor layer;
- a predetermined trench positioned on a surface of the second semiconductor layer and formed at a depth where the trench does not reach the first semiconductor layer;
- the gate electrode made of polysilicon and formed on a side wall of an upper portion of the trench with a gate insulation film interposed between the gate electrode and the side wall;
- the shield electrode formed on the center portion of the trench in a state where the shield electrode is spaced apart from the gate electrode;
- an insulation region configured to expand between the gate electrode and the shield electrode in the inside of the trench so as to make the shield electrode spaced apart from the gate electrode, and configured to expand along side walls and a bottom of the trench so as to make the shield electrode spaced apart from the side walls and the bottom of the trench;
- and
- a source electrode configured to be electrically connected to the shield electrode, wherein
- a thickness of the insulation region interposed between the gate electrode and the shield electrode is set larger than a thickness of the gate insulation film,
- assuming a thickness of the insulation region between a bottom of the shield electrode and a bottom of the trench as D1 and a thickness of the insulation region between the side wall of the shield electrode at the depth position of the bottom of the shield electrode and the side wall of the trench as d+D2, a relationship of D1<d+D2 is satisfied, and
- the insulation region between the side wall of the shield electrode at the depth position of the bottom of the shield electrode and the side wall of the trench is formed with a thermal oxide film and a CVD oxide film.
Dependencies are inferred from the claim text.