Semiconductor Back Electrode Segmentation for Contact Optimization
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Solution Overview
Problem
The existing reverse conduction semiconductor devices, such as RC-IGBTs, face limitations in designing the back surface side of the semiconductor substrate due to poor metal contact properties with both p-type and n-type semiconductor layers, restricting the flexibility in optimizing carrier injection efficiencies and increasing conduction losses.
Innovation Solution
The semiconductor device employs different materials for the back electrodes in the IGBT and diode regions, allowing for independent optimization of carrier injection efficiencies by using materials like AlSi, Ti, and MoSi2 for ohmic and Schottky connections, respectively, to improve metal contact properties and reduce conduction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single material is used for the back electrode in both IGBT and diode regions, then the device structure is simple, but the metal contact property cannot be optimized for both p-type and n-type semiconductor layers simultaneously
Solution Approach 1:
The back electrode is segmented into multiple regions with different materials: AlSi is used in the IGBT region (contacting p-type collector layer) while Ti is used in the diode region (contacting n-type cathode layer). This segmentation allows each region to have optimized metal contact properties for its specific semiconductor layer type, resolving the contradiction between structural simplicity and contact reliability.
Solution Approach 2:
Different materials are applied to different locations of the back electrode based on the local requirements of the semiconductor layers. The AlSi material provides low contact resistance for p-type layers in the IGBT region, while Ti provides low contact resistance for n-type layers in the diode region. This local quality approach optimizes metal contact properties for each specific region rather than using a uniform material throughout.
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 enhances the current cutoff capability and reduces conduction losses in both IGBT and diode regions, offering greater design flexibility and improved performance by tailoring metal contact properties to specific regions.
Implementation Method 1
a gate insulating film which is in contact with the fourth semiconductor layer, the third semiconductor layer, and the second semiconductor layer; a gate electrode which faces the third semiconductor layer via the gate insulating film
Implementation Method 2
using materials like AlSi, Ti, and MoSi2 for ohmic and Schottky connections, respectively, to improve metal contact properties
Implementation Method 3
using materials like AlSi, Ti, and MoSi2 for ohmic and Schottky connections, respectively, to improve metal contact properties
Data Source
AI summary
A semiconductor device in which a transistor and a diode are formed on a common semiconductor substrate is provided. The semiconductor substrate includes a transistor region in which a transistor is formed and a diode region in which a diode is formed. At least one first electrode on a second main surface side of the transistor region and at least one second electrode on a second main surface side of the diode region are made of different materials.