Multi-Peak Field Stop Proton Profile for Reverse Recovery Loss
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Solution Overview
Problem
Conventional semiconductor devices face challenges in achieving low reverse recovery loss and gentle reverse recovery characteristics, particularly in terms of peak current, tail current, and the rate of temporal change of reverse recovery voltage.
Innovation Solution
A semiconductor device is designed with an n-type semiconductor substrate, featuring a p-type semiconductor region on the front surface and an n-type field stop region on the rear surface, which includes protons as donors. The concentration distribution of these donors in the field stop region has multiple peaks, allowing for controlled carrier lifetime distribution and improved reverse recovery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional vertical semiconductor device structure is used, then the device can be manufactured with standard processes, but the reverse recovery loss is high and reverse recovery characteristics are poor
Solution Approach 1:
The patent applies parameter changes by creating a multi-peaked concentration distribution in the field stop region through controlled proton injection at different energies and amounts. This complex concentration profile (with 3-5 peaks) optimizes carrier lifetime distribution to reduce reverse recovery loss while managing the increased manufacturing complexity through precise parameter control during ion implantation
2Ease of manufacture
If the field stop region has a simple concentration distribution, then the manufacturing process is simpler, but the peak current and tail current during reverse recovery are not sufficiently reduced
Solution Approach 1:
The patent segments the field stop region concentration distribution into multiple discrete peaks (3-5 peaks) at different depths and concentrations. This segmentation allows independent optimization of carrier lifetime at different regions, reducing both peak current and tail current during reverse recovery while maintaining manufacturability through sequential proton injection processes
3Ease of operation
If proton injection is performed with single energy and amount, then the manufacturing process is straightforward, but the carrier lifetime distribution cannot be optimized for gentle reverse recovery
Solution Approach 1:
The patent employs periodic action by performing multiple sequential proton injection steps with different energies and amounts. Each injection step creates a distinct concentration peak, and the periodic repetition of this process with varying parameters builds the optimized multi-peaked distribution that achieves gentle reverse recovery characteristics
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 semiconductor device achieves reduced peak and tail currents during reverse recovery, leading to lower reverse recovery loss and a gentler rate of temporal change in reverse recovery voltage, thereby enhancing overall device performance.
Implementation Method 1
An n-type field stop region is formed in a rear surface side of the semiconductor substrate, the n-type field stop region including protons as a donor
Data Source
AI summary
A p-type semiconductor region is formed in a front surface side of an n-type semiconductor substrate. An n-type field stop (FS) region including protons as a donor is formed in a rear surface side of the semiconductor substrate. A concentration distribution of the donors in the FS region include first, second, third and fourth peaks in order from a front surface to the rear surface. Each of the peaks has a peak maximum point, and peak end points formed at both sides of the peak maximum point. The peak maximum points of the first and second peaks are higher than the peak maximum point of the third peak. The peak maximum point of the third peak is lower than the peak maximum point of the fourth peak.