SiC Schottky Junction Structure for Low Leakage and Forward Voltage
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Solution Overview
Problem
Conventional semiconductor devices face challenges in reducing forward voltage while maintaining reverse leakage current at comparable levels and minimizing variations in reverse leakage current.
Innovation Solution
A semiconductor device with a Schottky barrier diode made of SiC, featuring a molybdenum Schottky metal layer of 10 nm to 150 nm thickness, a flat or mildly uneven junction structure with SiC, and a guard ring configuration to alleviate stress and enhance inductive load resistance, along with a manufacturing method that includes heat treatment in a nitrogen atmosphere to prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the Schottky metal thickness is increased to reduce forward voltage, then the forward voltage decreases, but the reverse leakage current increases
Solution Approach 1:
The patent optimizes the Schottky metal thickness to a specific range (10-150 nm) to achieve the best balance between forward voltage and reverse leakage current. This parameter optimization resolves the contradiction by finding the optimal thickness that simultaneously reduces forward voltage while keeping reverse leakage current at acceptable levels.
2Use of energy by moving object
If the Schottky metal thickness is increased to reduce forward voltage, then the forward voltage decreases, but the stress applied to the SiC semiconductor layer increases
Solution Approach 1:
The patent specifies a thickness range of 10-150 nm for the Schottky metal layer, which is sufficient to reduce forward voltage while avoiding excessive stress on the SiC semiconductor layer. This parameter optimization resolves the contradiction between voltage reduction and stress management.
3Ease of manufacture
If conventional Schottky metal structures are used, then manufacturing is simpler, but the variation in reverse leakage current is large
Solution Approach 1:
The patent specifies a thickness range of 10-150 nm for the Schottky metal layer, which reduces the variation in reverse leakage current while remaining compatible with conventional manufacturing processes. This parameter control resolves the contradiction between manufacturing simplicity and product consistency.
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 forward voltage, suppresses reverse leakage current, and stabilizes its variation, improving inductive load resistance and preventing thermal destruction by reducing heat generation within the guard ring.
Implementation Method 1
a Schottky metal being made of molybdenum contacting a surface of the SiC semiconductor layer and having a thickness of 10 nm to 150 nm, in which the SiC semiconductor layer has a first junction portion contacting the Schottky metal
Implementation Method 2
a manufacturing method that includes heat treatment in a nitrogen atmosphere to prevent oxidation
Data Source
AI summary
A semiconductor device according to the present invention includes a first conductive-type SiC semiconductor layer, and a Schottky metal, comprising molybdenum and having a thickness of 10 nm to 150 nm, that contacts the surface of the SiC semiconductor layer. The junction of the SiC semiconductor layer to the Schottky metal has a planar structure, or a structure with recesses and protrusions of equal to or less than 5 nm.