Vertical Schottky Semiconductor Structure for Side-Surface Leakage
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Solution Overview
Problem
Power semiconductor devices with vertical structures face issues of leakage current and surface defects like cracking, chipping, and cleavage due to exposed wafer side surfaces.
Innovation Solution
A semiconductor device with a semiconductor layer covered by an insulating film from the electrode forming surfaces to the side surfaces, featuring a Schottky barrier diode configuration with a gallium oxide substrate and epitaxial layer, and a field plate structure to reduce leakage current and protect the side surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the wafer side surface is left exposed to simplify the manufacturing process, then the manufacturing complexity is reduced, but leakage current increases and surface defects occur
Solution Approach 1:
The patent extracts the problematic exposed side surface by introducing an insulating film that covers it. The insulating film is deposited to cover the side surface of the semiconductor wafer, effectively removing the harmful exposure of the side surface while maintaining manufacturing feasibility through standard deposition processes
Solution Approach 2:
The insulating film acts as an intermediary layer between the semiconductor wafer and the external environment. This intermediate layer prevents direct exposure of the side surface, thereby blocking leakage current paths and preventing surface defects without complicating the overall manufacturing process
2Reliability
If an insulating film is deposited to cover the side surface to reduce leakage current, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent segments the coverage area into specific regions: the insulating film is deposited to cover the side surface and extend onto the front surface up to the electrode edge, but is intentionally stopped before covering the electrode itself. This segmented approach ensures leakage current suppression while avoiding unnecessary complexity from complete coverage
Solution Approach 2:
The insulating film is applied selectively to specific locations where it is most needed - the side surface and the region near the electrode edge where leakage current is most likely to occur. The film thickness and coverage are optimized locally rather than uniformly applied throughout the entire device structure
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 solution effectively reduces leakage current and minimizes defects such as cracking and chipping on the side surfaces, enhancing the reliability and performance of the semiconductor device.
Implementation Method 1
an insulating film continuously formed from the first electrode forming surface to the side surface so as to cover the first edge
Implementation Method 2
the side surface is protected by the insulating film, making cracking, chipping, cleavage, and the like less likely to occur
Implementation Method 3
at least a part of the first electrode comes into Schottky-contact with the epitaxial layer
Data Source
Figure 1~2
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AI summary
An object of the present invention is to provide a vertical semiconductor device in which a leakage current flowing along the wafer side surface, and defects in the side surface, such as cracking, chipping and cleavage hardly occur. A semiconductor device includes a semiconductor layer 20 including first and second electrode forming surfaces 20a, 20b and side surface 20c, an anode electrode 40 formed on the first electrode forming surface 20a, a cathode electrode 50 formed on the second electrode forming surface 20b; an insulating film 30 continuously formed from the first electrode forming surface 20a to the side surface 20c so as to cover the first edge E1. According to the present invention, the side surface 20a of the semiconductor layer 20 is covered with the insulating film 30, so that a leak current flowing along the side surface 20c is reduced. Further, the side surface 20c is protected by the insulating film, making cracking, chipping, cleavage, and the like less likely to occur.