Lateral IGBT with Segmented Field Plates
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Solution Overview
Problem
High voltage power ICs require semiconductor structures with improved efficiency, reliability, and reduced on-state losses, which existing lateral IGBTs do not fully address, especially in achieving lower on-state resistance and higher breakdown voltage.
Innovation Solution
A semiconductor structure comprising a substrate with specific doping regions, wells, heavily doped regions, conductors, and dielectrics, forming a junction-isolated lateral IGBT with optimized doping concentrations and electrical connections to enhance current flow and reduce on-state resistance, while suppressing substrate current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lateral IGBT structure is used, then input impedance and gate control are improved, but on-state resistance remains higher than desired
Solution Approach 1:
The patent segments the IGBT structure into multiple independent cells with individual gate control, allowing each cell to be optimized for low on-state resistance while maintaining overall high input impedance through the parallel configuration of multiple cells
Solution Approach 2:
The patent applies different doping concentrations and junction depths in different regions of the semiconductor structure, creating locally optimized zones that reduce on-state resistance in the drift region while maintaining high breakdown voltage through appropriate junction characteristics
2Productivity
If doping concentration is increased to reduce on-state resistance, then current flow improves, but breakdown voltage decreases
Solution Approach 1:
The patent carefully controls and varies doping concentration parameters through multiple doping steps, creating a graded profile that increases carrier concentration in the drift region to reduce on-state resistance while maintaining appropriate junction depths to preserve breakdown voltage characteristics
Solution Approach 2:
The patent transitions from planar doping to three-dimensional junction structures with controlled depths and lateral dimensions, creating vertical and lateral field distribution patterns that simultaneously achieve low on-state resistance and high breakdown voltage through spatial separation of current flow and voltage blocking functions
3Ease of manufacture
If conventional IGBT structure is used, then manufacturing is simplified, but substrate current increases
Solution Approach 1:
The patent extracts and removes the parasitic bipolar transistor action from the conventional IGBT structure by implementing specific doping profiles and junction configurations that eliminate the feedback mechanism causing substrate current, while maintaining the basic lateral IGBT manufacturing process
Solution Approach 2:
The patent converts the potentially harmful substrate current effect into a beneficial low-impedance path by strategically placing heavily doped regions that guide current flow through controlled channels, transforming the parasitic effect into a useful current distribution mechanism
Data Source
AI summary
A semiconductor structure is provided. The semiconductor structure comprises: a substrate; a first doping region, a first well and a second doping region formed in the substrate; a plurality of first heavily doped regions formed in the first doping region; a plurality of conductors and a plurality of dielectrics formed on the substrate between the first heavily doped regions; a second heavily doped region formed in the first well; a third heavily doped region and a fourth heavily doped region formed in the second doping region; as well as a first gate electrode and a first gate dielectric. The first doping region, the first well, the second heavily doped region and the fourth heavily doped region have a first type of doping. The second doping region, the first heavily doped regions and the third heavily doped region have a second type of doping.