Semiconductor Device With Accumulation Region Doping
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Solution Overview
Problem
In semiconductor devices with trench gate structures, the density of holes implanted from collectors decreases near the emitters, leading to insufficient carrier density and high ON-resistance, which cannot be adequately reduced by conventional accumulation regions.
Innovation Solution
A semiconductor device design featuring a drift region, an accumulation region with higher doping concentration than the base region, and a gate trench structure that includes a dummy trench portion, where the accumulation region's doping concentration is optimized to enhance carrier density and reduce ON-resistance while maintaining adequate withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an accumulation region is provided below the base region to improve carrier density on the emitter side, then the ON-resistance can be reduced, but the hole accumulation is insufficient in conventional accumulation regions
Solution Approach 1:
The patent changes the doping concentration parameter of the accumulation region, making it higher than that of the base region. This parameter change enables sufficient hole accumulation in the accumulation region, thereby improving carrier density on the emitter side and reducing ON-resistance while maintaining adequate withstand voltage
2Reliability
If the doping concentration of the accumulation region is increased to reduce ON-resistance, then the ON-voltage decreases, but the withstand voltage may significantly decrease
Solution Approach 1:
The patent optimizes the doping concentration parameter of the accumulation region to be higher than the base region but within a specific range. This controlled parameter change reduces ON-resistance and ON-voltage while preventing significant decrease in withstand voltage
Solution Approach 2:
The patent creates different doping concentration zones: the accumulation region has higher doping concentration than the base region, which itself has higher doping concentration than the drift region. This local quality differentiation allows the accumulation region to provide sufficient holes for low ON-resistance while the lower-doped base and drift regions maintain adequate withstand voltage
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 design effectively reduces ON-resistance and ON-voltage while preventing a significant decrease in withstand voltage, by optimizing the doping concentration and structure of the accumulation region in relation to the base and drift regions.
Implementation Method 1
the density of holes implanted from collectors by conductivity modulation are decreased
Implementation Method 2
A maximum value of the doping concentration of the accumulation region may be greater than a maximum value of the doping concentration of the base region
Data Source
AI summary
A semiconductor device including: a semiconductor substrate; a drift region of first conductivity type that is formed in the semiconductor substrate; an accumulation region of first conductivity type that is formed above the drift region and has higher concentration than concentration of the drift region; a base region of second conductivity type that is formed above the accumulation region; and a gate trench portion that is formed extending from an upper surface of the semiconductor substrate to the drift region, passing through the base region and the accumulation region, wherein a maximum value of doping concentration of the accumulation region is greater than a maximum value of doping concentration of the base region will be provided.