Semiconductor Anode Doping Structure for Surge Current Resistance
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Solution Overview
Problem
Semiconductor devices face challenges in maintaining low forward losses and high surge current resistance, with weakly doped anode regions leading to poor surge current resistance and highly doped regions experiencing increased leakage current, making it difficult to achieve both low commutation losses and robustness.
Innovation Solution
A semiconductor device structure with a buried non-depletable anode doping region and a second conductivity type contact doping region, where the buried non-depletable portion is located below the contact doping region, allowing for efficient charge carrier management and enhanced surge current resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly doped anode regions are implemented to improve surge current resistance, then surge current resistance is improved, but leakage current increases
Solution Approach 1:
The anode doping region is segmented into multiple doping portions with different conductivity types and doping concentrations. Specifically, it includes a first conductivity type contact doping portion at the surface, a second conductivity type contact doping portion, and a buried non-depletable portion, allowing different regions to serve different functions: surface contact regions for current collection and buried regions for surge protection without excessive leakage
Solution Approach 2:
Different portions of the anode doping region are assigned different local properties: the contact doping portions have high doping concentrations for low contact resistance, while the buried non-depletable portion has specific doping characteristics to provide surge current resistance. This local differentiation allows each region to optimize for its specific function, preventing the trade-off between surge resistance and leakage
2Object-generated harmful factors
If weakly doped anode regions are implemented to reduce leakage current, then leakage current is reduced, but surge current resistance deteriorates
Solution Approach 1:
The anode doping region is divided into multiple functional portions including contact doping portions and a buried non-depletable portion. The contact doping portions use appropriate doping concentrations to maintain low leakage, while the buried non-depletable portion provides the necessary surge current resistance through its specific doping structure and depth
Solution Approach 2:
Different regions of the anode doping region have different doping concentrations and conductivity types optimized for their specific locations. The contact doping portions near the surface use doping levels suitable for low leakage operation, while the buried non-depletable portion at greater depth uses doping characteristics optimized for surge current handling, eliminating the need to compromise overall doping level
3Reliability
If high doping concentration is used to improve robustness, then robustness is improved, but commutation losses increase
Solution Approach 1:
The anode doping region is segmented into contact doping portions and a buried non-depletable portion. The contact doping portions have high doping concentrations to ensure low contact resistance and robust current collection, while the buried non-depletable portion is positioned and doped to provide robustness without creating excessive carrier storage that would increase commutation losses
Solution Approach 2:
The doping structure extends into the vertical dimension with the buried non-depletable portion located at a specific depth below the surface. This vertical positioning allows the high doping concentration to provide robustness and surge resistance without excessive lateral spread that would increase carrier flooding and commutation 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 proposed structure achieves low carrier flooding in front of the anode, improving surge current resistance and maintaining low commutation losses, while the buried non-depletable portion shields the anode contact, reducing electric field impact and preventing reverse current increase.
Implementation Method 1
incorporating dopants into a semiconductor substrate through a decelerating mask layer arranged at a surface of the semiconductor substrate
Implementation Method 2
the buried non-depletable portion shields the anode contact, reducing electric field impact and preventing reverse current increase
Implementation Method 3
annealing the semiconductor substrate and the epitaxial layer to enlarge the first doping area and the second doping area due to diffusion of dopants
Data Source
AI summary
A semiconductor device includes an anode doping region of a diode structure arranged in a semiconductor substrate. The anode doping region has a first conductivity type. The semiconductor device further includes a second conductivity type contact doping region having a second conductivity type. The second conductivity type contact doping region is arranged at a surface of the semiconductor substrate and surrounded in the semiconductor substrate by the anode doping region. The anode doping region includes a buried non-depletable portion. At least part of the buried non-depletable portion is located below the second conductivity type contact doping region in the semiconductor substrate.