Semiconductor Optical Device Contact Layer Lattice Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing semiconductor optical devices have limited flexibility in selecting materials for the second electrode, which restricts the reduction of driving voltage and contact resistance.
Innovation Solution
A semiconductor optical device with a multilayer structure where the contact layer has a thickness of four or less atomic layers, forming a pseudomorphic interface with the compound semiconductor layers, allowing for a specific lattice constant relationship that generates distortion and enables the use of materials with low work function values for the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a material with high work function value (such as Pt, Pd, Ni, Au) is used for the second electrode, then the contact resistance is reduced, but the degree of freedom for selecting materials is limited
Solution Approach 1:
The patent introduces an intermediate contact layer between the second electrode and the second compound semiconductor layer. This contact layer has a specific lattice constant relationship with both the semiconductor layer and the electrode material, enabling low-resistance contact with materials that have lower work function values. The contact layer acts as a mediator that bridges the interface between dissimilar materials, allowing flexible electrode material selection while maintaining good contact characteristics.
2Ease of manufacture
If the contact layer thickness is increased, then the ease of manufacture is improved, but the lattice distortion effect is reduced
Solution Approach 1:
The patent specifies that the contact layer thickness should be four or less atomic layers to maintain the lattice distortion effect. By controlling the thickness parameter within this specific range, the patent achieves optimal balance between manufacturability and the lattice constant relationship control. The thin thickness allows the lattice distortion to propagate effectively while still being manufacturable with standard thin-film deposition techniques.
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 reduces the driving voltage and enhances the flexibility in selecting materials for the second electrode, improving the contact resistance and overall performance of the semiconductor optical device.
Implementation Method 1
the contact layer has a thickness of four or less atomic layers, forming a pseudomorphic interface with the compound semiconductor layers, allowing for a specific lattice constant relationship that generates distortion
Data Source
AI summary
A semiconductor optical device has a multilayer structure 30 including a first compound semiconductor layer 31, an active layer 33, and a second compound semiconductor layer 32. A second electrode 42 is formed on the second compound semiconductor layer 32 through a contact layer 34. The contact layer 34 has a thickness of four or less atomic layers. When an interface between the contact layer 34 and the second compound semiconductor layer 32 is an xy-plane, a lattice constant along an x-axis of crystals constituting an interface layer 32A which is a part of the second compound semiconductor layer in contact with the contact layer 34 is x2, a lattice constant along a z-axis is z2, a length along an x-axis in one unit of crystals constituting the contact layer 34 is xc′, and a length along the z-axis is zc′, (zc′/xc′)>(z2/x2) is satisfied.