Field Plate Electrode Segmentation for Leakage Reduction
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Solution Overview
Problem
In semiconductor devices with circuits differing in power supply voltage, the connection of these circuits through a transistor leads to increased leakage current due to the field plate electrode functioning as a gate for a parasitic MOS transistor.
Innovation Solution
A semiconductor device design where the connection transistor is positioned at a part of the isolation region not surrounded by the isolation region, with a field plate electrode divided into portions, one overlapping the connection transistor and the other surrounding the circuit, to reduce leakage current by suppressing the operation of the parasitic MOS transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the field plate electrode is positioned over the connection transistor to provide electrical isolation, then the isolation effect is improved, but the leakage current increases due to parasitic MOS transistor operation
Solution Approach 1:
The field plate electrode is divided into a first field plate electrode and a second field plate electrode that are separated by a gap. The first field plate electrode is positioned over the connection transistor while the second surrounds the first circuit. This segmentation prevents the formation of a continuous parasitic MOS transistor gate, thereby reducing leakage current while maintaining electrical isolation functionality.
Solution Approach 2:
An insulating film is introduced between the first and second field plate electrodes in the gap region. This insulating film acts as an intermediary that electrically isolates the two field plate electrodes from each other, preventing parasitic MOS transistor operation at the connection transistor while allowing each field plate electrode to independently provide isolation coverage.
2Object-generated harmful factors
If the field plate electrode is divided into separate portions with a gap, then the leakage current is reduced, but the electrical isolation effectiveness may be compromised
Solution Approach 1:
The gap between the first and second field plate electrodes is selectively positioned at a location where parasitic MOS transistor operation would occur (over the connection transistor), while the rest of the field plate electrodes maintain continuous coverage for electrical isolation. This local modification addresses the leakage issue without compromising overall isolation effectiveness.
Data Source
AI summary
An isolation region includes an element isolation film and a field plate electrode. The field plate electrode overlaps the element isolation film and surrounds a first circuit when seen in a plan view. A part of the field plate electrode is also positioned on a connection transistor. A source and a drain of the connection transistor are opposite to each other through the field plate electrode when seen in a plan view. In addition, the field plate electrode is divided into a first portion including a portion that is positioned on the connection transistor, and a second portion other than the first portion.