Semiconductor Light Sources With Selective Diffusion Confinement
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Solution Overview
Problem
Semiconductor vertical cavity diodes face challenges in efficiently confining electrical current laterally to the same region that confines the optical mode, leading to reduced efficiency and increased mechanical strain, heat generation, and voltage losses.
Innovation Solution
The implementation of depleted heterojunction current blocking regions (DHCBRs) within the outer current blocking regions of the vertical cavity diodes, which utilize selective buried acceptor or donor diffusions to control electrical conductivity and direct current flow into the inner mode confinement region, thereby providing both current blocking and mode confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If standard intra-cavity oxide approach is used for lateral confinement, then optical mode confinement is achieved, but mechanical strain increases and drive voltage increases
Solution Approach 1:
The patent changes the material composition parameter by using AlGaAs layers with varying aluminum content (different refractive indices) to create index-guided confinement, replacing the oxide approach. This parameter change achieves optical confinement without the mechanical strain and voltage penalties of the oxide method.
Solution Approach 2:
The patent employs composite AlGaAs/GaAs heterostructure materials with different refractive indices to achieve optical confinement. The composite nature of these semiconductor layers provides both optical guidance and mechanical compatibility, avoiding the strain issues of oxide approaches.
2Area of stationary object
If standard intra-cavity oxide approach is used for lateral confinement, then optical mode confinement is achieved, but heat flow is blocked inside the vertical cavity diode
Solution Approach 1:
The patent changes from oxide material to semiconductor AlGaAs material, which maintains thermal conductivity pathways. This parameter change allows heat to flow efficiently through the device while still achieving optical confinement through refractive index differences.
3Use of energy by moving object
If lateral electrical confinement structures are added to confine current to optical mode region, then electrical injection efficiency improves, but device complexity increases
Solution Approach 1:
The patent makes the AlGaAs heterostructure layers serve multiple functions: they provide both optical mode confinement through refractive index differences and electrical current confinement through the same structural features. This multi-functionality eliminates the need for separate confinement structures, reducing device complexity while maintaining high electrical injection efficiency.
Solution Approach 2:
The patent merges the optical confinement function and electrical confinement function into a single integrated structure using AlGaAs/GaAs heterolayers. This consolidation achieves both types of confinement simultaneously without requiring additional separate components.
4Use of energy by moving object
If conventional current blocking regions are used, then current confinement is achieved, but optical mode confinement to the same region is reduced
Solution Approach 1:
The patent changes the confinement mechanism from electrical depletion regions to optical refractive index differences. By using AlGaAs layers with higher refractive index surrounded by GaAs, the patent achieves both current blocking and optical mode confinement in the same lateral region through material composition gradients.
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 enables high-efficiency electrical injection and optical mode confinement with reduced mechanical strain, lower operating voltages, and minimized thermal resistance, allowing for the creation of small, densely packed semiconductor light sources with improved beam quality and reduced leakage currents.
Implementation Method 1
selective buried acceptor or donor diffusions that control the electric conductivity in and around intracavity epitaxial phase-shifting layer or multiple layers to laterally confine one or more optical modes
Implementation Method 2
depleted heterojunction current blocking regions (DHCBRs) within an outer current blocking region of at least one of the upper minor, lower mirror, and the active region. A conducting channel is within the inner mode confinement region that is framed by the DHCBR, wherein the DHCBR functions to force current flow into the conducting channel
Data Source
AI summary
A semiconductor vertical resonant cavity light source includes an upper mirror and a lower minor that define a vertical resonant cavity. A first active region is within the vertical resonant cavity for light generation between the upper minor and lower mirror. The vertical resonant cavity includes an inner mode confinement region and an outer current blocking region. A depleted heterojunction current blocking region (DHCBR) is within the outer current blocking region of at least one of the upper minor, lower minor, and first active region. A conducting channel within the inner mode confinement region is framed by the DHCBR. The DHCBR forces current flow into the conducting channel during operation of the light source.