Semiconductor drift region field electrode coupling for on-resistance
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Solution Overview
Problem
There is a need to reduce the on-resistance and increase the voltage blocking capability of semiconductor devices with a drift region, as existing solutions face challenges in efficiently providing counter charges and managing the thickness of field electrodes, which affects the doping concentration and electrical resistance.
Innovation Solution
The semiconductor device incorporates a drift region of a first doping type, a junction, a field electrode structure with a field electrode dielectric having an opening, and a coupling region of a second doping type complementary to the first, where the field electrode structure includes a field stop region and a generation region, and the coupling region is electrically coupled to the device region and the field electrode, allowing for increased doping concentration without compromising voltage blocking capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping concentration of the drift region is increased to reduce on-resistance, then the on-resistance decreases, but the voltage blocking capability is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping distribution in the drift region through implantation. The doping concentration varies spatially, with higher concentrations in certain regions and lower concentrations in others, allowing different parts of the drift region to serve different functions: some regions provide high conductivity while others maintain voltage blocking capability
Solution Approach 2:
The patent changes the doping concentration parameter by implanting dopant atoms at specific doses and energies. The doping concentration is adjusted locally through controlled implantation processes, transforming the uniform doping parameter into a spatially varying parameter that optimizes both on-resistance and voltage blocking capability
2Reliability
If field electrodes are electrically connected to fixed electrical potential to provide counter charges, then counter charges are provided, but a thick field electrode dielectric is required which consumes space
Solution Approach 1:
The patent extracts the field electrode structure and replaces it with directly implanted dopant atoms in the drift region. This eliminates the need for separate field electrodes and their associated thick dielectric layers, while still providing the necessary counter charges through the implanted dopants that create space charge regions
3Adaptability or versatility
If several field electrodes are arranged distant to each other and connected to different voltage sources to bias to different potentials, then different potentials are achieved, but implementing multiple voltage sources is difficult
Solution Approach 1:
The patent changes the approach from using multiple voltage sources to using a single doping parameter variation. By implanting dopants at different concentrations and depths, the patent creates regions with different electrical characteristics, effectively achieving potential differences through material composition rather than multiple power supplies
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 configuration enhances the voltage blocking capability and reduces on-resistance by providing additional counter charges within the drift region, allowing for higher doping concentrations without increasing the thickness of the field electrode dielectric, thereby improving the overall performance of the semiconductor device.
Implementation Method 1
When the pn junction is reverse biased dopant atoms are ionized on both sides of the pn junction resulting in a space charge region that is associated with an electrical field. The doping concentration of the drift region may be increased without reducing the voltage blocking capability of the device when charges are provided in the drift region that may act as counter charges to ionized dopant atoms
Data Source
AI summary
A semiconductor device includes a drift region of a first doping type, a junction between the drift region and a device region, and a field electrode structure in the drift region. The field electrode structure includes a field electrode, a field electrode dielectric adjoining the field electrode, arranged between the field electrode and the drift region, and having an opening, and at least one of a field stop region and a generation region. The semiconductor device further includes a coupling region of a second doping type complementary to the first doping type. The coupling region is electrically coupled to the device region and coupled to the field electrode.