Trench type MOS rectifier and manufacturing method thereof

Abstract

The invention discloses a structure of a trench-type MOS rectifying element structure. The structure includes: a planar MOS rectifying structure is formed on platforms of an active zone and adjacent edges of the platforms are provided with active-zone trenches which are formed in an n- epitaxial layer of a heavily doped n+ semiconductor substrate. In the active-zone trenches, trench gate oxide layers are formed at the bottom parts and side walls of the trenches and p-type doped polycrystalline silicon layers are formed on the trench gate oxide layers. A top-part metal layer is formed on the active zone and connected with a grid electrode and a source electrode of the planar MOS structure and the polycrystalline silicon layers of the active-zone trenches. The invention also discloses a manufacturing method of the trench-type MOS rectifying element structure. The trench-type MOS rectifying element structure and the manufacturing method thereof use the trench-type structure so that the forward bias voltage VF is lower and reverse electricity leakage is smaller.

Description

technical field [0001] The invention relates to semiconductor elements, in particular to a new trench type MOS rectifier diode structure and a manufacturing method thereof. Background technique [0002] Schottky diode is an important power component, which is widely used in power supply switching, motor control, telecom switching, factory automation, electronic automation, etc. and many high-speed power switching applications. Schottky diodes are attractive because they have good performance, for example, under reverse bias, they have a reasonable leakage current (the leakage current of Schottky diodes is higher than that of ordinary PN diodes), low forward bias The voltage and the reverse recovery time tRR are short, and the high voltage of at least 250 volts can be blocked when the reverse bias voltage is applied. However, the leakage current of the Schottky diode is higher than that of the general PN type diode, and the leakage current is not a stable value but increases...

AI Technical Summary

Problems solved by technology

However, the leakage current of Schottky diodes is higher than that of ordinary PN diodes, and the leakage current is not stable but increases with the increase of reverse bias voltage. This is because the image charge potential barrier lowering

Another major disadvantage is that the reliability of the metal-semiconductor contact decreases as the temperature rises, which reduces the Schottky diode's ability to withstand forward and reverse surges.

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