Semiconductor Device Field Plate Segmentation for Leak Current Control
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Solution Overview
Problem
In semiconductor devices with circuits of different power voltages, the integration of a control circuit and a power control element leads to increased leak current due to the field plate electrode overlapping with the impurity region, degrading the separation between circuits.
Innovation Solution
A first circuit region is surrounded by a separation region with a repetitively disposed field plate electrode, and a coupling transistor connects the circuits, with the field plate electrode electrically coupled to the drain electrode on the first circuit region side and applying ground or power potential on the second circuit region side, utilizing a second conductivity type region to separate the transistor from other circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the field plate electrode is disposed to overlap with the impurity region to separate circuits, then the separation function between circuits is improved, but the leak current increases due to parasitic MOS transistor formation
Solution Approach 1:
The field plate electrode is divided into multiple segments along its length. Specific segments are positioned to overlap with the impurity region for circuit separation, while other segments are positioned away from the impurity region to avoid forming parasitic MOS transistors. This segmentation allows the field plate to simultaneously achieve both separation function and low leak current.
Solution Approach 2:
Different portions of the field plate electrode are given different spatial relationships with the impurity region. The portion that needs to overlap with the impurity region for separation is localized to specific segments, while other portions are positioned differently. This local differentiation allows the field plate to provide separation function where needed without creating parasitic effects elsewhere.
2Productivity
If circuits of different power voltages are integrated into one semiconductor device, then device integration is improved, but circuit separation becomes more difficult
Solution Approach 1:
The field plate electrode is segmented to provide localized separation functions within the integrated device structure. By dividing the field plate into multiple portions with different spatial relationships to the impurity region, the device achieves both high integration and effective circuit separation without compromising reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration suppresses the increase in leak current, effectively preventing the parasitic MOS transistor from turning on and maintaining the separation function between circuits.
Implementation Method 1
The field plate electrode is repetitively disposed in a folded manner or a spiral shape in a direction along an edge of the first circuit region
Data Source
AI summary
A field plate electrode is repetitively disposed in a folded manner or a spiral shape in a direction along an edge of a first circuit region. A coupling transistor couples a first circuit to a second circuit lower in supply voltage than the first circuit. A second conductivity type region is disposed around the coupling transistor. A part of the field plate electrode partially overlaps with the second conductivity type region. The field plate electrode is electrically coupled to a drain electrode of the coupling transistor at a portion located on the first circuit region side from a center thereof in a width direction of the separation region. A ground potential or a power potential of the second circuit is applied to the field plate electrode at a portion located on the second conductivity type region side from the center.