Nitride Semiconductor Photoelectric Surface with -C Polar Orientation
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Solution Overview
Problem
Conventional photoelectric surfaces using nitride semiconductor materials face challenges in achieving high quantum efficiency while maintaining low costs, with sapphire substrates being costly and difficult to process, and existing methods struggling to control the growth of smooth -c surfaces for enhanced polarization properties.
Innovation Solution
The method involves using silicon substrates with a (111) plane orientation for crystal growth, forming a buffer layer, and removing the substrate to achieve a nitride semiconductor crystal layer with a -c polar surface, which increases quantum efficiency by leveraging spontaneous and piezo polarization for improved photoelectron emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sapphire substrates are used for crystal growth, then high quality nitride semiconductor layers can be obtained, but material cost increases and mechanical processing time becomes extremely long
Solution Approach 1:
The invention changes the substrate material parameter from sapphire to silicon, and changes the surface orientation parameter from (0001)c to (111) plane. This parameter change allows the use of lower-cost silicon substrates while maintaining the ability to grow high-quality nitride semiconductor layers through controlled epitaxial growth processes.
Solution Approach 2:
The invention replaces expensive sapphire substrates with cheaper silicon substrates. The silicon substrates serve as temporary growth platforms during the epitaxial process and are subsequently removed, leaving only the desired nitride semiconductor layer on the final device structure.
2Productivity
If MOCVD growth method is used with (0001)c surface orientation, then crystal growth can proceed, but the +c plane growth direction makes it difficult to control -c surface growth and achieve highly smooth surfaces
Solution Approach 1:
Instead of attempting to grow the -c surface directly (which is difficult to control), the invention grows the crystal in the opposite direction (+c plane) on the silicon (111) substrate, then removes the substrate to expose the desired -c surface. This inverted approach converts a difficult growth problem into a controllable process.
Solution Approach 2:
The invention performs preliminary crystal growth on a sacrificial silicon substrate with (111) orientation, establishing the desired crystal structure and -c surface orientation before final substrate removal. This preliminary growth phase allows precise control of crystal orientation that would be difficult to achieve directly on the final substrate.
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 results in a photoelectric surface with increased quantum efficiency and lower production costs, as the -c polar surface enhances band bending and diffusion length, leading to higher photoelectron emission and improved device performance.
Implementation Method 1
Nitride type semiconductor materials have material specific polarization properties which include spontaneous polarization along the c axis of the crystal
Implementation Method 2
Nitride type semiconductor materials have material specific polarization properties which include spontaneous polarization along the c axis of the crystal and piezo polarization
Implementation Method 3
the quantum efficiency when an excited photoelectron is emitted by light entering a nitride semiconductor crystalline layer as a light absorbing layer
Data Source
AI summary
The object is to provide a photoelectric surface member which allows higher quantum efficiency. In order to achieve this object, a photoelectric surface member 1a is a crystalline layer formed by a nitride type semiconductor material, and comprises a nitride semiconductor crystal layer 10 where the direction from the first surface 101 to the second surface 102 is the negative c polar direction of the crystal, an adhesive layer 12 formed along the first surface 101 of the nitride semiconductor crystal layer 10, and a glass substrate 14 which is adhesively fixed to the adhesive layer 12 such that the adhesive layer 12 is located between the glass substrate 14 and the nitride semiconductor crystal layer 10.