Trench Isolation Layout for Faster Reverse Recovery in Semiconductors
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Solution Overview
Problem
Existing high-voltage semiconductor devices face challenges in improving device characteristics, particularly in reducing reverse recovery losses and achieving higher switching frequencies with minimal additional effort.
Innovation Solution
Incorporating trench isolation structures that extend from the surface into the transition region between an inner and an outer region, which reduce charge carrier lifetime and facilitate faster charge carrier removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional semiconductor device structures are used, then device simplicity is maintained, but reverse recovery losses are high and switching frequencies are limited
Solution Approach 1:
The device is segmented into distinct inner and outer regions separated by a transition region with trench isolation structures. This segmentation allows different regions to be optimized for different functions: the inner region for high-voltage blocking and the outer region for low-voltage switching, thereby reducing reverse recovery losses while maintaining manageable device complexity through functional分区
Solution Approach 2:
Different regions of the semiconductor device are given different doping concentrations and structural characteristics tailored to their specific functions. The transition region has a graded doping profile and includes trench isolation structures with specific geometries, creating local quality variations that reduce reverse recovery losses without requiring complete redesign of the entire device
2Productivity
If charge carrier lifetime is extended for better conduction, then on-state performance improves, but reverse recovery time increases and switching frequency decreases
Solution Approach 1:
The trench isolation structures extract and remove excess charge carriers from the transition region between the inner and outer regions. By providing recombination centers through the trenches, charge carriers are rapidly removed after switching, reducing reverse recovery time and enabling higher switching frequencies while maintaining low reverse recovery losses
Solution Approach 2:
The transition region with trench isolation structures acts as an intermediary between the inner high-voltage region and the outer low-voltage region. This intermediate structure facilitates controlled charge carrier management, allowing rapid removal of carriers during switching while maintaining adequate carrier concentration for low on-state resistance, thereby achieving both high switching frequency and low reverse recovery losses
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
The trench isolation structures enhance charge carrier recombination, leading to reduced reverse recovery losses and higher switching frequencies in semiconductor devices.
Implementation Method 1
Trench isolation structures, particularly extending from a surface into the transition region, reduce charge carrier lifetime and contribute to faster removal of charge carriers from the transition region
Data Source
AI summary
A semiconductor device includes a semiconductor layer, an electronic element and laterally separated trench isolation structures. The semiconductor layer includes an element region having an inner region, an outer region on opposite sides of the inner region, and a transition region that laterally separates the inner region and the outer region. The electronic element includes a first doped region formed in the inner region and a second doped region formed in the outer region. The trench isolation structures are formed at least in the transition region. Each trench isolation structure extends from a first surface of the semiconductor layer into the semiconductor layer.