Diffused β-Ga2O3 Photoconductive Layers Without Epitaxy
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Solution Overview
Problem
Current photoconductive semiconductor switches and optically addressable light valves face challenges with high development costs and laser damage issues due to the need for costly crystal growth equipment and fragile thin layers, especially when using transition metal-doped materials like SiC and Diamond, which require complex and expensive epitaxial growth or thinning processes.
Innovation Solution
The use of β-Ga2O3 semiconductor material doped with transition metals like copper, diffused into a Ga2O3 substrate to create a thin, controlled doped region, reducing the need for expensive epitaxial growth and offering higher laser damage thresholds, thus enabling more efficient and cost-effective production of photoconductive devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transition metal-doped materials like SiC and Diamond are used to create photoconductive devices, then photoresponsivity is improved, but manufacturing cost increases and device fragility worsens due to the need for expensive epitaxial growth equipment and fragile thin layers
Solution Approach 1:
The patent changes the material parameter from traditional SiC or Diamond to β-Ga2O3, which has a wider bandgap and allows for room-temperature operation. This material substitution enables the use of simpler diffusion-based doping techniques instead of expensive epitaxial growth, thereby improving manufacturability while maintaining high photoresponsivity through transition metal doping
Solution Approach 2:
The patent replaces expensive, fragile thin layers created through complex epitaxial growth with a more robust bulk β-Ga2O3 substrate that can be processed using simpler, more cost-effective diffusion techniques. The bulk material provides mechanical strength while the diffusion process creates the necessary doped regions, eliminating the need for fragile thin films
2Reliability
If transition metal-doped materials like SiC and Diamond are used to create photoconductive devices, then photoresponsivity is improved, but device complexity increases due to the need for complex epitaxial growth or thinning processes
Solution Approach 1:
The patent extracts the essential function of creating doped regions from the complex epitaxial growth process and achieves it through a simpler diffusion process. By taking out the need for expensive epitaxial equipment and complex thinning processes, the invention maintains the ability to create functional doped regions while dramatically simplifying the manufacturing workflow
Solution Approach 2:
Instead of growing thin doped layers on substrates (epitaxial approach), the patent inverts the approach by using a bulk substrate and diffusing dopants inward to create the doped regions. This inversion of the conventional approach simplifies the process by eliminating the need for precise thin film growth control and subsequent thinning operations
3Volume of moving object
If thin layers are used in photoconductive devices, then device size is reduced, but laser damage resistance worsens due to increased fragility and lower damage thresholds
Solution Approach 1:
The patent creates a composite structure where transition metal dopants are distributed within the β-Ga2O3 lattice to create doped regions with enhanced photoconductivity. This composite approach at the material level allows the bulk substrate to provide mechanical strength and laser damage resistance while the dopant regions provide the necessary photoresponsive functionality, eliminating the need for fragile thin films
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 allows for the creation of photoconductive semiconductor switches and optically addressable light valves with improved photoresponsivity and capacitance tuning, while eliminating the need for costly crystal growth equipment and reducing laser damage risks, leading to more efficient and cost-effective devices with enhanced performance.
Implementation Method 1
The β-Ga2O3 is doped with a transition metal (TM) such as copper to provide defect states (e.g., deep level traps) within the ultra wide band gap of the β-Ga2O3. In various designs, these defect states can provide conducting photocarriers when the transition metal doped semiconductor is illuminated with light of a sufficient energy to excite carriers from these defect states into, for example, the conduction band
Implementation Method 2
these defect states can provide conducting photocarriers when the transition metal doped semiconductor is illuminated with light of a sufficient energy to excite carriers from these defect states into, for example, the conduction band, thereby increasing the conductivity of the β-Ga2O3 layer
Data Source
AI summary
Various devices, systems and methods such as photonductive semiconductor switches (PCSS) and optically addressable light valves (OALVs) include a photoconducting β-Ga2O3 layer having a transition metal (TM) doped region formed by diffusion of transition metal into a β-Ga2O3 substrate. The diffusion of the TM into the β-Ga2O3 substrate provides for the controlled concentration and thickness of the doped TM region that is integrated into the bulk β-Ga2O3 substrate.