A compound trench gate Schottky device structure and its manufacturing method

Abstract

The invention provides a compound type trench gate shcottky device structure and a manufacturing method thereof. The compound type trench gate schottky device structure comprises an N type heavy doped substrate, an N type light doped silicon epitaxial layer combined with the surface of the N type heavy doped substrate, at least two grooves formed in the silicon epitaxial layer, silicon dioxide layers sedimentted at the bottoms of the grooves, first metal silicide layers formed in the lateral walls of the upper portions of the groove, conducting material layers arranged at the upper portions of the grooves in a filled mode, a second metal silicide layer formed on the surface of the silicon epitaxial layer and a front electrode layer formed on the surface of metal silicide. Thick gate oxide layer MOS structures are arranged at the bottoms of the grooves, and high potential barrier shcottky junctions are arranged on the lateral walls of the grooves. A compound type trench gate can effectively improve breakdown voltage and reduce capacitance of a device switch. By means of the compound type trench gate structures, the shcottky junctions are further formed in the lateral walls of the grooves. Thus, the forward breakdown drop voltage can be further reduced in large current, and the resistance of a device to surge impact is improved.

Description

technical field [0001] The invention relates to a semiconductor device and a manufacturing method thereof, in particular to a composite trench gate Schottky device structure and a manufacturing method thereof. Background technique [0002] With the continuous development of semiconductor technology, power devices, as a new type of device, are widely used in fields such as disk drives and automotive electronics. Power devices need to be able to withstand large voltage, current and power loads. However, existing devices such as MOS transistors cannot meet the above requirements. Therefore, in order to meet the needs of applications, various power devices have become the focus of attention. [0003] Schottky diodes are metal-semiconductor devices made of noble metals (gold, silver, aluminum, platinum, etc.) as the positive pole and N-type semiconductors as the negative pole, using the potential barrier formed on the contact surface of the two with rectification characteristics...

AI Technical Summary

Problems solved by technology

[0005] For the commonly used MOS structure using a single gate structure, it is desirable to use a thick oxide layer in terms of device breakdown voltage and switching capacitance; but in terms of process and cost, using a thick oxide layer will increase the trench width and reduce the forward conductivity of Schottky devices The effective area of ​​the conduction time increases the forward conduction voltage and loss. This contradiction restricts the optimization of the cost performance of the device.

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