Schottky Barrier Diode Terminal Layout for Moisture-Driven Peeling
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Solution Overview
Problem
The surface protection films and sealing materials used in semiconductor devices, such as polyimide and gel, tend to absorb moisture, leading to potential peeling at the interface between the surface electrode and the protection film, which can reduce insulation reliability by creating leak paths and cavities.
Innovation Solution
A semiconductor device design featuring a field insulating film and a surface electrode configuration where the outer peripheral end of the surface electrode in the corner portion is positioned on the inner side relative to the straight portion, reducing the field intensity and preventing the deposition of insulating materials like aluminum hydroxide, thereby minimizing peeling and enhancing insulation reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surface protection film (polyimide) and sealing material (gel) are used to cover the surface electrode, then the electrode is protected from environmental damage, but moisture is absorbed under high humidity conditions leading to peeling at the interface and reduced insulation reliability
Solution Approach 1:
A field insulating film is introduced as an intermediary layer between the surface electrode and the surface protection film. This mediator prevents direct contact between the electrode and moisture-absorbing protection film, eliminating the chemical reaction and peeling issues while maintaining protective coverage.
Solution Approach 2:
The harmful function of moisture absorption by the surface protection film is separated from the protective function. The protection film is kept for environmental protection while its harmful moisture absorption effect is isolated, preventing it from reaching and reacting with the surface electrode.
2Reliability
If the surface electrode extends to the outer periphery in the corner portion of the terminal region, then the electrical connection area is maximized, but insulating material deposits form at the electrode end leading to peeling of the surface protection film
Solution Approach 1:
The field insulating film serves as a mediator between the surface electrode and surface protection film in the corner region. It prevents the formation of insulating material deposits on the electrode surface that would otherwise cause peeling, while allowing the electrode to maintain its extended configuration for optimal electrical connection.
3Reliability
If the outer peripheral end of the surface electrode is positioned at the outer periphery of the terminal well region, then the electrical connection is optimized, but the field intensity becomes too high causing insulating material deposition and peeling
Solution Approach 1:
The field insulating film acts as a mediator that allows the surface electrode to be positioned at the outer periphery of the terminal well region for optimized electrical connection, while simultaneously managing the high field intensity to prevent insulating material deposition and maintain insulation reliability.
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 configuration effectively suppresses the generation of insulating deposits and peeling, thereby increasing the insulation reliability of the semiconductor device by maintaining a stable electrical connection and preventing leakage currents and aerial discharges.
Implementation Method 1
an electrical field generated when reverse voltage is applied to a main electrode of the semiconductor device is reduced by a depletion layer formed by a pn junction
Implementation Method 2
an electrical field generated when reverse voltage is applied to a main electrode of the semiconductor device is reduced by a depletion layer formed by a pn junction between the n-type semiconductor layer and the p-type guard ring region
Data Source
AI summary
An SBD includes: a terminal well region formed to surround an active region; a field insulating film formed to cover part of the terminal well region; a surface electrode formed on a drift layer on an inner side in relation to the field insulating film and electrically connected to the terminal well region; a surface protection film covering an end portion on an outer side of the surface electrode; and a back surface electrode formed on a back surface of a single crystal substrate. An end portion of an outer side of the surface electrode in the corner portion of the terminal region is located on an inner side in relation to the end portion of the outer side of the surface electrode in a straight portion of a terminal region based on a position of an end portion of an outer side of the terminal well region.