Semiconductor Field Plate With Stepwise Width Reduction
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Solution Overview
Problem
Semiconductor devices face challenges in achieving both low on-state resistance and high withstand voltage, as existing designs often compromise on one or the other due to limitations in field plate electrode width and insulating film thickness distribution.
Innovation Solution
A semiconductor device design featuring a field plate electrode with stepwise width reduction in the vertical direction, combined with a graded impurity concentration in the drift layer and a stair-shaped insulating film, which moderates electrical potential and enhances electric field distribution, allowing for reduced on-state resistance while maintaining high withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating film thickness is increased to maintain withstand voltage, then withstand voltage is maintained, but manufacturing complexity increases
Solution Approach 1:
The insulating film is segmented into multiple regions with different thicknesses corresponding to the stepped field plate electrode structure. The first insulating film portion has a first thickness and the second insulating film portion has a second thickness. This segmentation matches the electrode structure, providing adequate insulation where needed while simplifying manufacturing in other areas.
Solution Approach 2:
Different thicknesses of the insulating film are applied to different locations based on local requirements. Thicker insulation is provided where higher voltage isolation is needed, while thinner insulation suffices in lower voltage regions. This local quality approach maintains withstand voltage without uniformly increasing complexity throughout the entire device.
Data Source
AI summary
A semiconductor device includes a first electrode, a first semiconductor layer on the first electrode, a second semiconductor layer on the first semiconductor layer, a third semiconductor layer on the second semiconductor layer, a second electrode in electrical contact with the third semiconductor layer, a gate electrode, a first insulating film between the side surface of the third semiconductor layer and the gate electrode, a field plate electrode, and a second insulating film. The field plate has an upper portion adjacent to the gate electrode and a lower portion having a width less than a width of the upper portion. The second insulating film has a first portion between the field plate electrode's upper portion and the first semiconductor layer and a second portion between the field plate electrode's lower portion and the first semiconductor layer, the second portion having a width greater than the width of the first portion.