Semiconductor Device Field Dielectric Layer Height
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MOS power transistors face challenges in achieving a balance between low on-state resistance and high breakdown voltage, particularly in withstanding high source-drain voltages and conducting large currents while maintaining efficient isolation between the field plate and drift region.
Innovation Solution
The semiconductor device incorporates an isolation trench with a lateral isolation layer, a source and drain region, a body and drift region, a gate electrode adjacent to the body region, and a field dielectric layer between the drift region and the field plate, where the top surface of the field dielectric layer is positioned higher than the lateral isolation layer, enhancing breakdown voltage and on-current performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a predetermined thickness of the isolation layer is disposed between the field plate and the silicon drift region, then the on-current is improved, but the breakdown voltage characteristic deteriorates
Solution Approach 1:
The patent transitions from a planar isolation layer to a vertically structured field dielectric layer with stepped configuration. The field dielectric layer is disposed at different heights relative to the drift region, creating a three-dimensional structure that provides both electrical isolation and mechanical support without compromising breakdown voltage
Solution Approach 2:
The isolation structure is segmented into multiple regions: a first field dielectric layer portion disposed at a first height and a second field dielectric layer portion disposed at a second height. This segmentation allows different portions to serve different functions - one portion provides electrical isolation while another provides mechanical support and stress relief
2Reliability
If the top surface of the field dielectric layer is disposed at a greater height than the top surface of the lateral isolation layer, then the lateral insulation is improved, but the device complexity increases
Solution Approach 1:
The field dielectric layer combines multiple functions into a single structure: it provides lateral insulation between adjacent devices, vertical isolation between the drift region and field plate, and mechanical stress relief. This merging of functions reduces the need for separate isolation structures and simplifies the overall device architecture despite the stepped configuration
Data Source
AI summary
A semiconductor device formed in a semiconductor substrate includes an isolation trench in the semiconductor substrate to laterally insulate adjacent components of the semiconductor device. A lateral isolation layer is disposed in the isolation trench. The semiconductor device further includes a source region and a drain region, and a body region and a drift region disposed between the source region and the drain region. The semiconductor device additionally includes a gate electrode adjacent to at least a portion of the body region and a field plate adjacent to at least a portion of the drift region. A field dielectric layer is disposed between the drift region and the field plate. A top surface of the field dielectric layer is disposed at a greater height measured from a first main surface of the semiconductor substrate than a top surface of the lateral isolation layer.