SiC Semiconductor Electrode Metallization via Ion Implantation
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Solution Overview
Problem
Silicon carbide (SiC) semiconductor devices face challenges in reducing contact resistance for metallic electrodes due to the lack of suitable materials with a work function that lowers the barrier between electrodes and n-type impurity layers, making it difficult to form low contact-resistance electrodes while maintaining oxidation resistance.
Innovation Solution
Incorporating a SiC metallic region with elements like Mg, Ca, Sr, Ba, Sc, Y, La, and lanthanoids into the SiC substrate through ion implantation and heat treatment, which metallizes the SiC by introducing these elements into the carbon sites, reducing contact resistance and eliminating energy barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metallic materials are used for electrodes on n-type SiC impurity layers, then oxidation resistance is maintained, but contact resistance remains high due to energy barrier
Solution Approach 1:
The invention changes the chemical composition parameter of the electrode material by incorporating specific elements (Mg, Ca, Sr, Ba, Sc, Y, La, or lanthanoids) into the SiC lattice. This compositional modification alters the electronic structure and work function of the electrode, enabling it to reduce the energy barrier with n-type SiC while maintaining oxidation resistance through the protective SiO2 layer that forms on the SiC surface.
Solution Approach 2:
The invention creates a composite structure where metallic elements are integrated into the SiC crystal lattice, forming a hybrid material system. The SiC matrix provides oxidation resistance through surface passivation, while the embedded metallic elements reduce the contact resistance by modifying the electronic properties at the electrode-SiC interface.
2Object-affected harmful factors
If ion implantation with metallic elements is performed to reduce contact resistance, then energy barrier is reduced, but processing temperature must be controlled to avoid adverse effects
Solution Approach 1:
The invention optimizes the thermal processing parameters by conducting heat treatment at specifically controlled temperatures (700-1200°C). This temperature range is sufficient to activate the implanted metallic elements and reduce contact resistance while remaining below the threshold that would cause device degradation, threshold voltage shifts, or film delamination.
Solution Approach 2:
The invention performs ion implantation as a preliminary step before final device fabrication and testing. By pre-introducing the metallic elements into the SiC lattice and conducting heat treatment early in the process, the contact resistance is reduced before subsequent processing steps, preventing later issues with electrode performance.
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
This approach effectively reduces contact resistance between the SiC substrate and electrodes, enabling lower ON resistance in SiC semiconductor devices without adverse effects on device characteristics, such as variations in threshold value or film peeling, and allows for lower-temperature processing.
Implementation Method 1
a side of the SiC semiconductor layer of n-type semiconductor opposite to the first electrode is subjected to ion implantation with at least one element selected from the group of Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), Sc (scandium), Y (yttrium), La (lanthanum), and lanthanoid
Implementation Method 2
after the ion implantation with the element, heat treatment is carried out to metallize the SiC semiconductor layer with the element implanted therein
Implementation Method 3
metallizes the SiC by introducing these elements into the carbon sites
Data Source
AI summary
A semiconductor device according to an embodiment includes: a first electrode; a SiC semiconductor layer including n-type semiconductor; and a second electrode including a SiC metallic region made of metal in contact with the SiC semiconductor layer, the SiC metallic region provided on a side of the SiC semiconductor layer opposite to the first electrode, the SiC metallic region containing at least one element selected from the group of Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), Sc (scandium), Y (yttrium), La (lanthanum), and lanthanoid (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu).