BAlGaN Semiconductor Layer for Short-Wavelength UV Emission
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Solution Overview
Problem
Current ultraviolet semiconductor light emitting devices face challenges in producing short-wavelength light due to increased crystal defects and difficulty in converting to p-type materials, as high Al content is required for shorter wavelengths, limiting their practical application.
Innovation Solution
A semiconductor layer composed of BxAlyGazN, formed using the laser assisted metalorganic vapor phase epitaxy technique, with a base plate of BeO, TiB2, ScB2, VB2, YB2, MnB2, MgB2, or CrB2, allowing for the production of light in the 190 nm to 300 nm range with reduced Al content and improved crystalline characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the Al quantity in the AlGaN mixed crystal or AlGaInN mixed crystal is increased to produce shorter wavelength light, then the light emission wavelength decreases, but crystal defects increase and p-type conversion becomes difficult
Solution Approach 1:
The patent changes the compositional parameters of the semiconductor material from AlGaN/AlGaInN to BAlGaN/BAlGaInN, specifically adjusting the ratio of Group III elements (Al, Ga, In) to achieve the desired wavelength while maintaining crystal quality. This material system substitution allows for shorter wavelengths without the severe degradation in crystal quality that occurs with high-Al-content AlGaN
Solution Approach 2:
The patent employs composite semiconductor materials with multiple elements (B, Al, Ga, In, N) in specific combinations. The BAlGaN and BAlGaInN mixed crystals represent composite materials that combine the advantages of different element combinations to achieve short-wavelength emission while maintaining acceptable crystal quality and enabling p-type conversion
2Illumination intensity
If the Al quantity in the AlGaN mixed crystal or AlGaInN mixed crystal is increased to produce shorter wavelength light, then the light emission wavelength decreases, but the difficulty of p-type conversion increases
Solution Approach 1:
The patent changes the material composition from Al-based to B-based mixed crystals, which fundamentally alters the doping characteristics. The BAlGaN and BAlGaInN material system allows for effective p-type doping even at compositions that yield short wavelengths, whereas AlGaN becomes increasingly difficult to dope p-type as Al content increases
3Reliability
If AlGaN type semiconductor light emitting devices are used with GaN base plate, then crystal growth can be achieved, but the Al quantity is limited due to crystal defects
Solution Approach 1:
The patent employs BAlGaN and BAlGaInN composite materials that provide a more favorable compositional space for short-wavelength emission. These composite materials maintain good crystal growth characteristics on GaN base plates while enabling shorter wavelengths through adjusted element ratios, unlike AlGaN where high Al content causes severe crystal defects
Solution Approach 2:
The patent changes the material composition parameters from Al-rich to B-rich mixed crystals, allowing for shorter wavelengths through different compositional pathways. The BAlGaN system provides a parameter space where both good crystal growth and short wavelength emission can be achieved, overcoming the limitations of the AlGaN system
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 solution enables the production of short-wavelength semiconductor light emitting devices with high efficiency and good light emission characteristics, reducing crystal defects and facilitating p-type conversion, thus overcoming limitations of existing AlGaN type materials.
Implementation Method 1
formed with a laser assisted metalorganic vapor phase epitaxy technique
Implementation Method 2
laser assisted metalorganic vapor phase epitaxy technique
Data Source
AI summary
A semiconductor layer contains, as a principal constituent, a Groups III-V semiconductor compound, which may be represented by the general formula: BxAlyGazN, wherein x represents a number satisfying the condition 0<x<1, y represents a number satisfying the condition 0≦y<1, and z represents a number satisfying the condition 0<z<1, with the proviso that x+y+z=1, the semiconductor layer having been formed with a laser assisted metalorganic vapor phase epitaxy technique. A semiconductor light emitting device comprises the semiconductor layer and may be constituted as a semiconductor laser or a light emitting diode.