A trench type Schottky device and its manufacturing method

Abstract

The invention relates to a trench type Schottky device and a manufacturing method thereof. The structure is that the cell structure is hexagonal, the top of the trench is inclined, and the metal interface of the barrier layer is lower than the interface of the contact metal layer in the vertical direction. Methods: 1) growing an oxide layer on the epitaxial wafer; 2) etching the trench by photolithography; 3) generating gate oxide in the trench; 4) filling the trench with polysilicon; 5) etching back the polysilicon; 6) removing the oxide layer by wet method; 7 ) High temperature thermal oxidation; 8) SiN deposition, ILD silicon dioxide layer deposition; 9) Schottky contact hole photolithography, wet silicon dioxide removal; 10) SiN / thermal oxide layer dry etching; 11) Schottky barrier metal sputtering; 12) barrier metal alloy / barrier metal removal; 13) HPD deposition; 14) contact metal sputtering; 15) contact metal photolithography; 16) back gold thinning. Advantages: maximize the utilization of the cell area, and have a high degree of matching with the process flow; the barrier metal is better accumulated inside the trench; avoid leakage channels.

Description

technical field [0001] The invention relates to a trench type Schottky device and a manufacturing method thereof, in particular to a trench type Schottky diode structure and a manufacturing method thereof. Background technique [0002] Trench-type Schottky diodes are common power devices for semiconductors, which were invented by utilizing the MOS effect of metal-semiconductor-silicon. Its main feature is that as the reverse voltage increases, the trenches are pinched off in advance through the MOS effect, and the electric field strength drops to zero before reaching the silicon surface, avoiding breakdown on the surface and improving the blocking ability. [0003] In the prior art, the manufacturing process of trench-type Schottky diodes is as follows: growing oxide layer as a hard mask layer-trench photolithography-trench etching-polysilicon filling-polysilicon back-etching-contact hole photolithography-contact Hole etching - barrier metal sputtering - barrier metal alloy...

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Problems solved by technology

[0004] In the above processes of the prior art, it is necessary to precisely control the etching depth of the contact hole, the intra-chip uniformity of the etching rate, and the thickness of the barrier; there is a situation where the contact metal directly contacts the silicon and causes leakage ( figure 1 )

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