Grooved Semiconductor Substrate for Low Contact Resistance
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Solution Overview
Problem
There is a need to reduce contact resistance between a semiconductor substrate and an electrode in semiconductor devices, particularly in RC-IGBTs, to lower on-voltage and prevent snapback operations.
Innovation Solution
A method involving the formation of a groove on the semiconductor substrate by locally heating it with a light-transmissive oxide film, followed by electrode formation, which increases the contact area and reduces resistance, and a semiconductor device configuration with specific impurity regions and electrode structures that inhibit current flow from the IGBT to the diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact area between electrode and semiconductor substrate is increased, then contact resistance is reduced, but the device structure becomes more complex
Solution Approach 1:
The invention transforms the flat two-dimensional contact interface into a three-dimensional grooved structure. By forming grooves on the semiconductor substrate surface, the contact area between electrode and substrate is significantly increased without requiring additional layers or complex multi-layer structures. The groove geometry (depth, width, shape) provides an extra dimensional parameter to optimize contact area while maintaining structural simplicity.
Solution Approach 2:
The grooved structure creates local variations in the substrate surface, concentrating the contact area enhancement in specific regions where grooves are formed. This localized modification allows the electrode to achieve better contact precisely where needed, while leaving other areas of the device structure unchanged and simple.
2Reliability
If the on-voltage of IGBT is reduced, then device performance is improved, but snapback operations may occur
Solution Approach 1:
The grooved structure is formed locally in the collector region surrounding the cathode region, creating localized electrical field modifications. This local structural change alters current distribution and electric field concentration in specific areas, enabling lower on-voltage without triggering snapback in critical regions.
Solution Approach 2:
The grooves introduce curved surfaces and rounded geometries into the otherwise planar device structure. These curved interfaces modify electric field distribution and current flow paths, reducing field concentration that could lead to snapback while maintaining low on-voltage through improved contact geometry.
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 and on-voltage of the IGBT, inhibits snapback operations, and enhances the anchor effect of the electrode on the substrate, leading to improved device performance and stability.
Implementation Method 1
the oxide film has a high light transmittivity, and the surface of the semiconductor substrate is locally heated
Implementation Method 2
the surface of the semiconductor substrate is locally heated
Implementation Method 3
this method makes it possible to locally melt the surface of the semiconductor substrate without melting the oxide film
Data Source
AI summary
A technology for reducing contact resistance between a semiconductor substrate and an electrode is provided. A provided method for manufacturing a semiconductor device includes: forming an oxide film 62 on a surface 12b of a semiconductor substrate 12 by bringing the surface 12b into contact with ammonia-hydrogen peroxide water mixture; forming a groove 60 on the surface 12b by irradiating light to heat the surface 12b covered with the oxide film 62; removing the oxide film 62 to expose the surface 12b; and forming an electrode 16 on the exposed surface 12b.