SiC Semiconductor Contact Resistance via Localized Doping
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Solution Overview
Problem
The formation of a contact region with high impurity concentration in silicon carbide semiconductor devices requires a large dose and longer implantation time, which interferes with the efficiency of manufacturing these devices.
Innovation Solution
A silicon carbide semiconductor device with a first impurity region, a second impurity region, and a third impurity region, where the electrode is connected to the second and third regions, with specific depth profiles to reduce contact resistance and manufacturing time, allowing for a shallower p+ contact region formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large dose amount is used to form a contact region at a deep position, then the contact resistance is reduced, but the implantation time period increases
Solution Approach 1:
The patent applies local quality by creating a p+ contact region with high impurity concentration at a specific location (deeper than the source region) rather than uniformly doping the entire structure. This localized high-dose implantation reduces contact resistance at the electrode interface without requiring long implantation times for the whole device, thus resolving the contradiction between contact resistance reduction and manufacturing time.
Solution Approach 2:
The patent changes the impurity concentration parameter by forming a p+ contact region with impurity concentration of 1×10^19 to 1×10^21 atoms/cm³, which is significantly higher than the source region concentration of 1×10^16 to 1×10^19 atoms/cm³. This parameter change enables effective contact resistance reduction while controlling the implantation process to maintain reasonable time periods through optimized doping profiles.
2Reliability
If ion implantation is used to form a contact region high in impurity concentration, then the contact resistance is reduced, but the manufacturing efficiency decreases
Solution Approach 1:
The patent applies preliminary action by forming the p+ contact region in a controlled sequence where the source region is doped first, followed by the p+ contact region formation. This preliminary structuring allows subsequent high-dose implantation to be more efficient and targeted, reducing overall manufacturing time while achieving the required contact resistance levels.
Solution Approach 2:
The patent uses partial action by applying high-dose ion implantation only to the specific contact region area rather than the entire semiconductor layer. This selective doping approach reduces the total implantation time and increases manufacturing efficiency while still achieving sufficiently low contact resistance at the electrode interface.
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 enables the manufacturing of silicon carbide semiconductor devices with lower contact resistance and improved manufacturing efficiency by reducing the dose amount and implantation time required for forming the p+ contact region.
Implementation Method 1
ion implantation or epitaxial growth has been used for forming an active region in a method of manufacturing a silicon carbide semiconductor device
Implementation Method 2
ion implantation or epitaxial growth has been used for forming an active region in a method of manufacturing a silicon carbide semiconductor device
Data Source
AI summary
The silicon carbide semiconductor layer includes a first impurity region, a second impurity region, and a third impurity region. Turning to a first position at which an impurity concentration 1/10 as high as a highest impurity concentration is exhibited in a concentration profile of an impurity having the first conductivity type in a direction perpendicular to the main surface in the third impurity region and a second position at which an impurity concentration 1/10 as high as a highest impurity concentration is exhibited in a concentration profile of an impurity having the second conductivity type in the direction perpendicular to the main surface in the second impurity region, a first depth from the main surface to the first position is shallower than a second depth from the main surface to the second position. The electrode is electrically connected to the second impurity region and the third impurity region.