SiC Electrode Contact Structure With Metal Silicide Interface
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Solution Overview
Problem
The challenge in manufacturing semiconductor devices using silicon carbide is the high contact resistance between the silicon carbide layer and the metal electrode, which hinders the realization of low-loss and high-temperature operation.
Innovation Solution
A method involving ion implantation of p-type and carbon impurities into a silicon carbide layer, followed by heat treatment, oxidation, etching, and formation of metal silicide layers with specific metal elements like nickel, palladium, or chromium, to reduce carbon vacancies and enhance the contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a metal electrode is directly formed on a silicon carbide layer, then the device structure is simple, but the contact resistance between the silicon carbide layer and the metal electrode is high
Solution Approach 1:
A metal silicide layer is introduced as an intermediary between the silicon carbide layer and the metal electrode. This intermediate layer facilitates better electrical contact by reducing the contact resistance, while the multi-layer structure remains relatively simple to manufacture.
Solution Approach 2:
The contact resistance is reduced by changing the physical and chemical parameters of the interface between silicon carbide and metal electrode. Specifically, a metal silicide layer is formed through controlled reaction between metal and silicon carbide, creating an intermediate phase with optimized electrical properties for low contact resistance.
2Reliability
If ion implantation and multiple heat treatments are performed to reduce carbon vacancies, then the contact resistance is reduced, but the manufacturing process becomes complex
Solution Approach 1:
Carbon vacancies are reduced through preliminary ion implantation of carbon and heat treatment before forming the metal silicide layer. This preliminary action prepares the silicon carbide layer by reducing carbon vacancies and improving the crystal structure, which subsequently enables lower contact resistance when the metal electrode is formed.
Solution Approach 2:
Multiple process steps are merged and integrated into a coordinated sequence: ion implantation of carbon, heat treatment for vacancy reduction, and metal silicide layer formation are combined in an integrated manufacturing flow. This merging optimizes the overall process efficiency while achieving the desired low contact resistance.
3Reliability
If the acceptor concentration in the p-type region is increased, then the contact resistance is reduced, but the device requires more complex doping processes
Solution Approach 1:
The acceptor concentration in the p-type region is increased through preliminary ion implantation of carbon and heat treatment before metal electrode formation. This preliminary doping action creates a high-concentration p-type region that reduces contact resistance, and the doping is performed at a specific stage when the silicon carbide layer is already prepared.
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 method effectively reduces contact resistance by increasing the acceptor concentration in the p-type region, allowing for lower contact resistance and improved device performance.
Implementation Method 1
performing first ion implantation of ion-implanting a p-type impurity into a silicon carbide layer... performing second ion implantation of ion-implanting carbon (C) into the silicon carbide layer
Implementation Method 2
performing a first heat treatment for activating the p-type impurity... performing a second heat treatment for causing the silicon carbide layer to react with the first metal film to form a metal silicide layer
Implementation Method 3
performing a first oxidation treatment of oxidizing the silicon carbide layer
Implementation Method 4
performing an etching treatment of etching the silicon carbide layer in an atmosphere containing hydrogen gas
Data Source
AI summary
Provided is a method for manufacturing a semiconductor device, the method including: performing first ion implantation ion-implanting a p-type impurity into a silicon carbide layer; performing second ion implantation ion-implanting carbon (C) into the silicon carbide layer; performing a first heat treatment activating the p-type impurity; performing a first oxidation treatment oxidizing the silicon carbide layer; performing an etching treatment etching the silicon carbide layer in an atmosphere containing hydrogen gas; forming a first metal film containing at least one metal element selected from the group consisting of nickel, palladium, platinum, and chromium; performing a second heat treatment causing the silicon carbide layer to react with the first metal film to form a metal silicide layer containing the at least one metal element; and forming a second metal film having a chemical composition different from a chemical composition of the first metal film.