Semiconductor Contact Layer Electrode Design for Resistance Reduction
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Solution Overview
Problem
Existing semiconductor devices face challenges in reducing contact resistance and thermal resistance while maintaining reliability, particularly when trying to increase data transfer rates by reducing ridge width, as this can lead to structural destabilization and decreased production capacity due to increased contact layer thickness and stress concentration.
Innovation Solution
A semiconductor device with a contact layer having a wider upper surface, back surface, and side surface, where the electrode contacts the entire surface of the contact layer from the upper end to the lower end of the side surface, formed using electroless plating, increasing the contact area without lengthening the protruding portion, thus reducing contact and thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ridge width is reduced to decrease parasitic capacitance, then the data transfer rate increases, but the contact resistance increases due to reduced contact area
Solution Approach 1:
The electrode is extended from only contacting the upper surface to contacting the side surface as well, transitioning from a 2D contact area to a 3D contact area. This dimensional expansion allows the contact area to be increased without increasing the ridge width, thus reducing parasitic capacitance while maintaining low contact resistance
Solution Approach 2:
The electrode structure merges the upper surface contact and side surface contact into a unified contact region. This combined contact approach maximizes the effective contact area between the electrode and contact layer, reducing contact resistance without requiring an increase in ridge width
2Reliability
If the contact layer thickness is increased to maintain contact area when ridge width is reduced, then contact resistance decreases, but the production capacity of epitaxial apparatus deteriorates
Solution Approach 1:
Instead of increasing contact area by increasing thickness (one dimension), the solution extends the electrode contact to the side surface, utilizing three-dimensional space. This allows sufficient contact area to be achieved without increasing the contact layer thickness, maintaining production capacity
3Reliability
If the contact layer thickness is increased to maintain contact area, then contact resistance decreases, but stress concentration occurs at the base portion leading to reliability deterioration
Solution Approach 1:
The electrode contact is extended to the side surface, distributing the contact stress over a larger three-dimensional area rather than concentrating it at the base portion. This stress distribution reduces stress concentration and improves structural reliability while maintaining low contact resistance
4Reliability
If the protruding portion of contact layer is lengthened to increase contact area, then contact resistance decreases, but the structural stability deteriorates
Solution Approach 1:
The electrode contact is extended to the side surface within the existing ridge structure, achieving increased contact area without lengthening the protruding portion. This maintains the structural stability of the ridge while reducing contact resistance through three-dimensional contact
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 effectively reduces contact and thermal resistance while preventing structural destabilization, enhancing reliability and enabling higher speed performance in optical communication systems without compromising production capacity or reliability.
Implementation Method 1
forming an electrode by electroless plating in such a manner that the electrode contacts the upper surface, the side surface and the back surface of the contact layer
Data Source
AI summary
A semiconductor device according to the present invention includes a substrate, an active layer provided on the substrate, a cladding layer provided on the active layer, a contact layer provided on the cladding layer, the contact layer having an upper surface, a back surface which is a surface on an opposite side to the upper surface, and a side surface connecting the upper surface and the back surface, the contact layer is larger in width than the cladding layer; and an electrode that is in contact with the upper surface of the contact layer and the side surface of the contact layer from an upper end to a lower end of the side surface of the contact layer.