Schottky Diode Doping Segmentation for Breakdown Voltage
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Solution Overview
Problem
Conventional Schottky diodes face limitations in achieving high breakdown voltage under reverse bias and current spreading per unit area when forward biased, due to restricted n-type dopant concentration in the n drift region.
Innovation Solution
The Schottky diode device incorporates a p-type semiconductor structure with first and second n-type doping regions of different concentrations, where the second n-type doping region surrounds the first, and a third n-type doping region is formed with an anode and cathode electrode configuration, enhancing breakdown voltage and current spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the n-type dopant concentration in the n drift region is kept low (≤2.0×10^16 atoms/cm³) to improve breakdown voltage under reverse bias, then breakdown voltage is improved, but current spreading per unit area is restricted when forward biased
Solution Approach 1:
The patent applies local quality by creating two distinct n-type doping regions with different dopant concentrations within the n drift region. The first n-type doping region has a lower concentration (≤2.0×10^16 atoms/cm³) to ensure high breakdown voltage, while the second n-type doping region has a higher concentration (≥1.0×10^17 atoms/cm³) to enable effective current spreading. This spatial differentiation of doping concentrations allows each region to fulfill its specific functional requirement without compromising the other.
2Ease of manufacture
If a single n-type doping concentration is used in the n drift region to simplify manufacturing, then manufacturing is easier, but both breakdown voltage and current spreading cannot be optimized simultaneously
Solution Approach 1:
The patent segments the n drift region into two functionally distinct n-type doping regions: a first n-type doping region with lower concentration for breakdown voltage control, and a second n-type doping region with higher concentration for current spreading enhancement. This segmentation allows each region to be optimized independently for its specific purpose, resolving the contradiction between manufacturing simplicity and performance optimization.
3Productivity
If the n-type dopant concentration is increased to improve current spreading, then current spreading per unit area is improved, but breakdown voltage under reverse bias decreases
Solution Approach 1:
The patent applies local quality by creating two distinct n-type doping regions with different dopant concentrations within the n drift region. The first n-type doping region has a lower concentration (≤2.0×10^16 atoms/cm³) to ensure high breakdown voltage, while the second n-type doping region has a higher concentration (≥1.0×10^17 atoms/cm³) to enable effective current spreading. This spatial differentiation of doping concentrations allows each region to fulfill its specific functional requirement without compromising the other.
Data Source
AI summary
A Schottky diode device is provided, including a p-type semiconductor structure. An n drift region is disposed over the p-type semiconductor structure, wherein the n drift region comprises first and second n-type doping regions having different n-type doping concentrations, and the second n-type doping region is formed with a dopant concentration greater than that in the first n-type doping region. A plurality of isolation structures is disposed in the second n-type doping region of the n drift region, defining an anode region and a cathode region. A third n-type doping region is disposed in the second n-type doping region exposed by the cathode region. An anode electrode is disposed over the first n-type doping region in the anode region. A cathode electrode is disposed over the third n-type doping region in the cathode region.