Shanghai Huahong Grace Semiconductor Manufacturing Corporation

Longjie Zhao

Tao Wang

Jiye Yang

Wei Zhang

Yi Lu

Jia Pan

Junjun Xing

Xukun Zhang

Xuan Huang

Chong Chen

Xiaoxiang Sun

A method for manufacturing a trench gate device includes: forming a trench in a substrate with a super junction structure; forming a gate dielectric layer in the trench; forming a polysilicon gate by filling a portion of the trench with polysilicon; forming an intermediate dielectric layer in the trench; forming an auxiliary polysilicon layer by filling a gap in the trench with polysilicon; forming a source region of the trench gate device in the substrate; depositing an interlayer dielectric layer, and forming contacts in the interlayer dielectric layer, wherein the polysilicon gate, the auxiliary polysilicon layer, and the source region are led out from the contacts; and connecting the led-out auxiliary polysilicon layer to the led-out source region.

Trench gate device and method for making the same

The present disclosure discloses a trench gate semiconductor device, wherein a trench gate includes a trench formed in a semiconductor substrate, and a gate oxide layer formed on a bottom surface and a side surface of the trench; the gate oxide layer is formed by stacking a first oxide layer and a second oxide layer; the first oxide layer is a furnace tube thermal oxide layer; the second oxide layer is a PECVD oxide layer; the gate oxide layer has a thermally densified structure processed by means of RTA. The present disclosure also discloses a method for manufacturing a trench gate semiconductor device. The present disclosure can increase BVGSS of the device, without affecting the threshold voltage of the device, with simple processes and low costs.

Trench gate semiconductor device and method for making the same

An IGBT device comprises a super-junction structure arranged in a drift region and formed by a plurality of N-type pillars and a plurality of P-type pillars which are alternately arrayed. Device cell structures of the IGBT device are formed in an N-type epitaxial layer at the tops of super-junction cells. Each device cell structure comprises a body region, a gate structure and an emitter region. N-type isolation layers having a doping concentration greater than that of the N-type epitaxial layer are formed between the bottom surfaces of the body regions and the top surfaces of the P-type pillars and are used for isolating the body regions from the P-type pillars. The super-junction structure and the N-type isolation layers can increase the current density of the device, decrease the on-state voltage drop of the device and reduce the turn-off loss of the device.

IGBT device

A super-junction structure is formed by alternately arrayed pluralities of N-pillars and of P-pillars. The P-pillars are formed by P-type materials filled in super-junction trenches. The super-junction trenches are formed in an N-type epitaxial layer, each formed by a bottom trench and a top trench stacked together. A side angle of the bottom trenches is greater than 90&#xb0;, and the width of the bottom surface of each bottom trench is greater than that of the top surface of the trench. The side angle of the top trenches is smaller than 90&#xb0;, and the width of the bottom surface of each top trench is smaller than the top surface of the trench. The super-junction trenches are of a waisted structure. The bottom trenches increase the bottom width of the super-junction trenches and improve the depletion of the bottoms of the N-pillars, increasing the breakdown voltage of the super-junction structure.

Super-junction structure and method for manufacturing same

A trench gate manufacturing method includes the following steps: Step 1, forming a trench in the surface of a semiconductor substrate; Step 2, forming a first oxide layer; Step 3, selecting a coating according to the depth-to-width ratio of the trench and forming the coating completely filling the trench; Step 4, etching back the coating through a dry etching process; Step 5, conducting wet etching on the first oxide layer with the coating reserved at the bottom of the trench as a mask so as to form a gate bottom oxide; Step 6, removing the coating; and Step 7, growing a gate oxide. By adoption of the trench gate manufacturing method, a BTO can be realized at a low cost, and can be well-formed in trenches with smaller depth-to-width ratios and thus is suitable for forming BTOs in trenches with various depth-to-width ratios, thereby having a wider application range.

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Shanghai, China

Longjie Zhao