Semiconductor Device Recessed Source Region Ohmic Electrode
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Solution Overview
Problem
Conventional semiconductor devices face challenges in size reduction due to the need for ohmic electrodes in each cell, which hinders miniaturization efforts.
Innovation Solution
The semiconductor device incorporates a substrate with recesses and conductivity regions, allowing for reduced ohmic electrode placement by connecting source regions across recesses, and includes additional recesses for independent cell design and electric field relaxation, enabling smaller cell sizes and reduced on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ohmic electrode is provided in each cell surrounded by the gate trench, then reliable current conduction is achieved, but cell size reduction is hindered
Solution Approach 1:
The invention merges the function of ohmic electrodes across adjacent cells by providing a common ohmic electrode on the back surface that serves multiple cells simultaneously. This eliminates the need for individual ohmic electrodes in each cell, thereby reducing cell size while maintaining reliable current conduction through the shared electrode structure.
Solution Approach 2:
The invention moves the ohmic electrode from the front surface (within each cell) to the back surface of the semiconductor substrate. This dimensional relocation allows the ohmic electrode to span multiple cells without interfering with the gate trench structure, enabling cell size reduction while preserving electrical functionality.
2Power
If the substrate includes multiple first recesses with gate electrodes, then high breakdown voltage and low loss are achieved, but the number of required ohmic electrodes increases
Solution Approach 1:
The back surface ohmic electrode serves as a universal electrode for multiple cells simultaneously, performing the same electrical function for all adjacent cells. This multi-functional design reduces the total number of ohmic electrodes required while maintaining the high breakdown voltage and low loss performance achieved through the multiple gate electrode structures.
3Reliability
If ohmic electrodes are placed in each cell, then proper electrical contact is ensured, but manufacturing complexity increases
Solution Approach 1:
The invention combines multiple electrical contact functions into a single back surface ohmic electrode structure. This reduces the number of separate manufacturing steps required for electrode formation, simplifying the fabrication process while ensuring proper electrical contact through the shared electrode that serves multiple cells.
Data Source
AI summary
The substrate is made of a compound semiconductor and has a plurality of first recesses, each of which opens at one main surface thereof and has a first side wall surface. The gate insulating film is disposed on and in contact with the first side wall surface. The gate electrode is disposed on and in contact with the gate insulating film. The substrate include: a source region having first conductivity type and disposed to face itself with a first recess interposed therebetween, when viewed in a cross section along the thickness direction; and a body region having second conductivity type and disposed to face itself with the first recess interposed therebetween. Portions of the source region facing each other are connected to each other in a region interposed between the first recess and another first recess adjacent to the first recess, when viewed in a plan view.