Semiconductor device with spicular-shaped field plate structures and a current spread region

Abstract

The invention provides a semiconductor device with spicular-shaped field plate structures and a current spread region. A semiconductor device includes: a semiconductor substrate having a drift regionof a first conductivity type, a body region of a second conductivity type formed above the drift region, and a source region of the first conductivity type separated from the drift region by the bodyregion; rows of spicular-shaped field plate structures formed in the semiconductor substrate, the spicular-shaped field plate structures extending through the source region and the body region into the drift region; stripe-shaped gate structures formed in the semiconductor substrate and separating adjacent rows of the spicular-shaped field plate structures; and a current spread region of the firstconductivity type formed below the body region in semiconductor mesas between adjacent ones of the spicular-shaped field plate structures and which are devoid of the stripe-shaped gate structures. The current spread region is configured to increase channel current distribution in the semiconductor mesas.

Description

Background technique [0001] Power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) typically have field plates for charge compensation, providing significant improvements in area-specific on-resistance (RxA). Some power transistor cell designs use striped trenches for the field plates, where the gate electrodes are in the same striped trenches as the field electrodes. Other power transistor cell designs place the field plate in a deep pin trench in the center of the cell, and surround the pin trench with a separate trench that includes the gate electrode. The increased semiconductor mesa area between the deep pin trenches in the center of the cell and the surrounding gate trenches is expected to provide even lower overall on-resistance. [0002] Unlike the strip field plate design, the cell design with the needle field plate trench at the center of the cell does not integrate the gate electrode in the field plate trench. Instead, the gate electrode is moved to a ...

AI Technical Summary

Problems solved by technology

However, conventional cell designs with pin-shaped field plate trenches do not allow easy reduction of gate charge and gate-drain charge due to the significant increase in total gate area compared to the gate-stripe layout

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