Conductive Adhesive Semiconductor Contact
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Solution Overview
Problem
The high manufacturing cost of semiconductor optoelectronic devices, such as photovoltaic cells, is a significant challenge due to the complex and costly processes involved in depositing rear metal contact layers.
Innovation Solution
The use of an electrically conductive adhesive that forms a direct ohmic contact with both the doped contact layer of the semiconductor portion and an electrical conductor, allowing all electrical current to pass through by carrier tunneling, eliminating the need for a rear metal contact layer and simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rear metal contact layer is deposited onto the semiconductor substrate by electron-beam, thermal, sputtering or electroplating deposition, then electrical current can be collected and passed through the conductive epoxy to the metal conductor, but the manufacturing cost becomes high due to the complex and costly deposition processes
Solution Approach 1:
The invention extracts and eliminates the rear metal contact layer from the conventional semiconductor device structure. Instead of depositing metal layers through complex processes, the patent uses a conductive epoxy adhesive applied directly to the semiconductor substrate to establish electrical contact with the metal conductor, thereby removing the costly deposition steps while maintaining current collection functionality
Solution Approach 2:
The invention changes the electrical contact mechanism from metal-to-metal ohmic contact to a semiconductor-to-conductive adhesive contact. The conductive epoxy adhesive contains conductive particles that enable electrical current passage from the semiconductor substrate directly to the metal conductor, fundamentally altering the contact parameter from deposited metal layer to particle-based conductive medium
2Reliability
If a rear metal contact layer is deposited to provide ohmic contact with the semiconductor substrate, then electrical current flow is enabled, but the device structure becomes more complex and fabrication is more difficult
Solution Approach 1:
The invention merges the functions of the rear metal contact layer and the adhesive bonding layer into a single conductive epoxy adhesive layer. This consolidated structure simultaneously provides mechanical bonding between the semiconductor substrate and support substrate while enabling electrical current flow, thereby eliminating the need for separate metal contact and adhesive layers
Solution Approach 2:
The conductive epoxy adhesive performs multiple functions: it provides mechanical bonding between the semiconductor substrate and support substrate, establishes electrical contact for current collection, and eliminates the need for separate metal deposition layers. This multi-functional material simplifies the overall device structure and fabrication process
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 reduces manufacturing costs while maintaining the electrical performance of the devices comparable to conventional devices with rear metal contact layers, as demonstrated by the similar performance metrics of photovoltaic cells without and with rear metal contact layers.
Implementation Method 1
all electrical current passing to or from the semiconductor portion travels through the electrically conductive adhesive by carriers tunnelling between the doped contact layer of the semiconductor portion and the electrically conductive adhesive
Data Source
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AI summary
A semiconductor device (30) comprises a semiconductor portion (23, 24), a support substrate (20), and an electrical conductor (21) for passing an electrical current to or from the semiconductor portion (23, 24). The semiconductor portion (23, 24) is bonded to the support substrate (20) by an electrically conductive adhesive (22), which is in direct ohmic contact with a doped contact layer (23) of the semiconductor portion (23, 24) and which is additionally in direct ohmic contact with the electrical conductor (21). The electrically conductive adhesive (22) is arranged such that all electrical current passing to or from the semiconductor portion (23, 24) travels through the electrically conductive adhesive (22) by carriers tunnelling between the doped contact layer (23) of the semiconductor portion (23, 24) and the electrically conductive adhesive (22).