Power Semiconductor Deep Trench Isolation Leakage Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power semiconductor devices face challenges in achieving both high breakdown voltages and low on-resistance, with drift zones requiring specific doping levels that can lead to increased chip size and costs, and leakage paths at the semiconductor-oxide interface hindering blocking behavior.
Innovation Solution
The method involves forming a deep trench isolation with a compensation semiconductor region of higher doping concentration than the semiconductor layer, which compensates for fixed charges trapped in the trench, ensuring effective field-effect compensation and reducing leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the doping level of the wafer material is reduced to enable small drift zone dimensions, then the breakdown voltage capability is improved, but the on-resistance increases
Solution Approach 1:
The patent applies local quality by creating a compensation semiconductor region with higher doping concentration specifically at the drift zone-trench interface, while maintaining low doping levels in the bulk drift zone. This localized doping adjustment compensates for fixed charges at the interface without increasing overall drift zone resistance, thus resolving the contradiction between breakdown voltage capability and on-resistance.
2Strength
If deep trench isolation is formed to isolate high voltage regions, then voltage blocking is improved, but leakage paths occur at the semiconductor-oxide interface
Solution Approach 1:
The patent converts the harmful fixed charges trapped in the trench oxide into a beneficial effect by introducing a compensation semiconductor region with opposite polarity doping. This region compensates for the fixed charges, eliminating the leakage paths they create while maintaining the voltage blocking capability of the deep trench isolation structure.
3Area of stationary object
If the chip size is reduced by optimizing drift zone dimensions, then manufacturing cost is improved, but voltage blocking capability deteriorates
Solution Approach 1:
The patent changes the doping concentration parameter locally at the drift zone-trench interface by forming a compensation semiconductor region with higher doping level. This parameter change allows for reduced drift zone dimensions while maintaining voltage blocking capability, thus enabling smaller chip size without sacrificing performance.
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 approach allows for the formation of power semiconductor devices with improved voltage blocking capabilities and reduced leakage currents, enabling efficient operation at different voltage levels while maintaining low overall doping levels and chip size.
Implementation Method 1
An amount of the first dopants in the compensation semiconductor region is such that a field-effect of fixed charges of the first electric charge type, which are trapped in the trench, is at least partly compensated next to the wall.
Data Source
AI summary
A method of forming a power semiconductor device includes providing a semiconductor layer of a first conductivity type extending to a first side and having a first doping concentration of first dopants providing majority charge carriers of a first electric charge type in the layer, and forming a deep trench isolation including forming a trench which extends from the first side into the semiconductor layer and includes, in a vertical cross-section perpendicular to the first side, a wall, forming a compensation semiconductor region of the first conductivity type at the wall and having a second doping concentration of the first dopants higher than the first doping concentration, and filling the trench with a dielectric material. The amount of first dopants in the compensation semiconductor region is such that a field-effect of fixed charges of the first electric charge type which are trapped in the trench is at least partly compensated.