Semiconductor Well Isolation via Dopant Separation Regions
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Solution Overview
Problem
Existing semiconductor devices face challenges in efficiently diverting currents and protecting gate trenches from high electric fields, leading to increased costs and chip area usage due to the need for complex trench structures to insulate deep semiconductor well regions.
Innovation Solution
A semiconductor device design featuring a semiconductor body with a drift region, transistor cells, and external semiconductor well regions, where a separation region with complementary conductivity type dopants is used to isolate and extend between the well regions, reducing the need for double trench structures and minimizing chip area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep semiconductor well regions are arranged external of transistor cells, then current diversion and gate trench protection are improved, but device complexity and manufacturing cost increase due to the need for insulating trench structures
Solution Approach 1:
The patent extracts the insulating function from complex double trench structures and transfers it to separation regions formed by dopant diffusion. The separation regions with dopants of first conductivity type are introduced between deep semiconductor well regions with dopants of second conductivity type, eliminating the need for insulating trenches while maintaining electrical isolation. This reduces structural complexity while preserving the protective function.
Solution Approach 2:
The patent changes the approach from geometric isolation (trenches) to material-based isolation (dopant concentration gradients). By creating separation regions with specific dopant concentrations and conductivity types, the patent achieves electrical isolation between deep well regions without requiring physical trench structures. The continuous transition of dopant concentration provides both isolation and mechanical integrity.
2Reliability
If deep semiconductor well regions are arranged external of transistor cells, then current diversion and gate trench protection are improved, but chip area increases due to space required for well regions and insulating structures
Solution Approach 1:
The patent merges the functions of deep well regions, separation regions, and isolation structures into a unified dopant-based system. The separation regions are formed through dopant diffusion processes that can be integrated with existing transistor cell fabrication, eliminating the need for separate insulating trench structures. This consolidation reduces the total area required while maintaining all necessary functions.
Solution Approach 2:
The separation regions act as intermediary zones between deep semiconductor well regions, providing electrical isolation through dopant concentration gradients rather than requiring physical barriers. These intermediary regions with complementary conductivity types enable current diversion and protection functions while occupying minimal space compared to traditional trench structures.
3Reliability
If complex trench structures are used to insulate deep semiconductor well regions, then electrical isolation is improved, but production cost increases
Solution Approach 1:
The patent replaces mechanical/physical isolation structures (trenches requiring etching, filling, and planarization) with a material-based isolation system using dopant diffusion. The separation regions are created through standard semiconductor doping processes, eliminating the need for complex mechanical trench structures. This substitution significantly reduces manufacturing steps and associated costs while maintaining effective electrical isolation.
Data Source
AI summary
A semiconductor device includes transistor cells formed inside a semiconductor body. First and second semiconductor well regions have second conductivity type dopants and are arranged external of the transistor cells. The first semiconductor well region is arranged between two transistor cells and the second semiconductor well region is electrically connected with a load contact. A separation region has first conductivity type dopants and extends from a surface of the semiconductor body along the vertical direction and is arranged between and in contact with each of the first and second semiconductor well regions. The first semiconductor well region extends at least as deep as each of body regions of two transistor cells. A transition in a first lateral direction between the separation and first semiconductor well regions extends continuously from the surface to a point in the semiconductor body at least as deep as each body region of two transistor cells.