Quantum Well Intermixing for Non-Absorbing Laser Mirror Facets
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Solution Overview
Problem
The existing methods for fabricating high-power semiconductor lasers face limitations due to catastrophic optical damage (COD) at the mirror surfaces, which restricts the output power and reliability of the devices.
Innovation Solution
A manufacturing method involving a semiconductor stack layer with an aluminum nitride layer grown and annealed to achieve quantum well intermixing, increasing the energy gap at the mirror surface and forming a non-absorbing mirror structure, thereby enhancing the COD threshold and device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional mirror surfaces are used in laser devices, then the device structure is simple, but the output power is limited due to catastrophic optical damage (COD) at the mirror surfaces
Solution Approach 1:
The patent changes the material composition parameter of the mirror surface by forming an aluminum gallium nitride layer with high aluminum content (x≥0.5 in AlxGa1-xN), which fundamentally alters the energy band structure to create a larger energy gap. This parameter change transforms the mirror surface from being susceptible to COD to having high resistance against optical damage, enabling higher output power operation
Solution Approach 2:
The patent employs composite material structure by combining aluminum gallium nitride (AlGaN) with different aluminum compositions with the underlying semiconductor layers. The high-aluminum-content AlGaN layer is integrated with the laser active region, creating a composite structure that leverages the wide bandgap properties of AlGaN to protect against COD while maintaining laser functionality
2Reliability
If the energy gap at the mirror surface is increased to reduce absorption coefficient, then the COD threshold is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent replaces complex post-growth processing methods (such as ion implantation or thermal diffusion) with a direct epitaxial growth approach using metal organic chemical vapor deposition (MOCVD). The desired high-aluminum-content AlGaN layer is grown in-situ with precise compositional control, eliminating the need for additional complex manufacturing steps while achieving the required energy gap elevation
Solution Approach 2:
The patent achieves the energy gap modification by controlling the aluminum content parameter during epitaxial growth (x≥0.5 in AlxGa1-xN). This single parameter change during growth directly creates the high-energy-gap mirror surface structure, avoiding multiple processing steps and reducing overall manufacturing complexity while achieving high COD threshold
3Reliability
If quantum well intermixing is performed to elevate the energy gap, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent introduces an aluminum nitride (AlN) buffer layer as an intermediary between the semiconductor substrate and the quantum well structure. This AlN buffer layer serves as a nucleation layer that facilitates controlled intermixing during annealing, enabling precise elevation of the energy gap at the mirror surface while maintaining manufacturing control and reducing precision requirements for the annealing 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
The method effectively elevates the energy gap at the mirror surface, improving the reliability and COD threshold of semiconductor devices by using the annealed aluminum nitride layer, which offers superior mechanical and thermal properties, thus reducing the likelihood of optical damage and maintaining output power stability over time.
Implementation Method 1
The aluminum nitride layer is annealed to achieve quantum well intermixing
Implementation Method 2
An aluminum nitride layer is grown on the second type semiconductor layer
Data Source
AI summary
A manufacturing method of a semiconductor device includes: providing a semiconductor stack layer, wherein the semiconductor stack layer includes a first type semiconductor layer, a quantum well layer, and a second type semiconductor layer stacked in sequence; growing an aluminum nitride layer on the second type semiconductor layer; and annealing the aluminum nitride layer to achieve quantum well intermixing.