Semiconductor Device N-type Carrier Stored Layer Proton Implantation
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Solution Overview
Problem
Existing semiconductor devices face challenges in controlling the variation of threshold voltage while reducing on-voltage and manufacturing complexity, particularly in forming a carrier stored layer with precise impurity concentration distribution.
Innovation Solution
A semiconductor device design featuring an n-type semiconductor substrate with a p-type base layer, an n-type emitter layer, a trench gate, and an n-type carrier stored layer with a concentration gradient that is higher towards the substrate, allowing for proton implantation to achieve a low concentration near the p-type base layer, thereby reducing threshold voltage variation and lowering on-voltage, and can be easily manufactured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If normal phosphorus implantation and thermal diffusion are used to form a carrier stored layer with low concentration near the p-type base layer, then threshold voltage variation is reduced, but it is difficult to control the implantation of impurities
Solution Approach 1:
The patent changes the type of impurity from phosphorus (group V element) to boron (group III element). This parameter change allows the carrier stored layer to be formed by simple ion implantation without requiring complex concentration gradient control through thermal diffusion, thereby reducing manufacturing difficulty while maintaining low threshold voltage variation
Solution Approach 2:
The patent uses boron ions which can be easily implanted and provide the desired electrical characteristics without requiring complex processing. The boron-based carrier stored layer achieves the necessary function with simpler, more controllable implantation processes compared to phosphorus diffusion methods
2Power
If the concentration of the carrier stored layer is increased to reduce on-voltage, then on-voltage is lowered, but threshold voltage variation increases
Solution Approach 1:
The patent changes the impurity type to boron and adjusts the concentration to 1×10^16 to 1×10^18 atoms/cm³. This parameter change allows achieving low on-voltage through adequate carrier storage while the boron properties and controlled concentration prevent excessive threshold voltage variation, resolving the trade-off between on-voltage and threshold voltage stability
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 solution effectively reduces threshold voltage variation and lowers on-voltage while simplifying the manufacturing process, ensuring stable device performance and efficiency.
Implementation Method 1
a proton is implanted in the n-type carrier stored layer
Implementation Method 2
with respect to the n-type carrier stored layer, a concentration gradient directing from a position of a peak concentration to the back surface side of the n-type semiconductor substrate is larger than a concentration gradient directing from the position of the peak concentration to the p-type base layer
Implementation Method 3
store holes from the back surface in the n−-type semiconductor substrate to activate conductivity modulation and reduce the resistance of the n−-type semiconductor substrate
Data Source
AI summary
A semiconductor device includes: an n-type semiconductor substrate; a p-type base layer formed on a surface of the n-type semiconductor substrate; an n-type emitter layer formed on the p-type base layer, a trench gate penetrating through the p-type base layer and the n-type emitter layer; an n-type carrier stored layer formed between the n-type semiconductor substrate and the p-type base layer and having a higher concentration than that of the n-type semiconductor substrate; and a p-type collector layer formed on a back surface of the n-type semiconductor substrate, wherein with respect to the n-type carrier stored layer, a concentration gradient directing from a position of a peak concentration to the back surface of the n-type semiconductor substrate is larger than a concentration gradient directing from the position of the peak concentration to the p-type base layer, and a proton is implanted in the n-type carrier stored layer as an impurity.