Nitride Crystal Substrate Heating Accuracy via Free Carrier Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for heating nitride crystal substrates in semiconductor manufacturing lack accuracy and reproducibility, particularly in setting heating conditions based on the absorption coefficient, leading to variations in crystallinity and device performance.
Innovation Solution
A nitride crystal substrate with a specific absorption coefficient expression (α=nKλa) in the 1 μm to 3.3 μm wavelength range, allowing for precise control of heating through free carrier absorption, ensuring high accuracy and reproducibility in heating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional heating methods are used for nitride crystal substrates, then heating can be performed, but heating accuracy and reproducibility are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the free electron concentration (n) in the nitride crystal substrate to achieve a specific absorption coefficient range. By adjusting the doping concentration of n-type impurities to 1×10^18 to 1×10^19 atoms/cm³, the absorption coefficient at 2 μm wavelength is controlled to 1.2 to 48 cm⁻¹, enabling accurate and reproducible heating when irradiated with infrared light.
2Measurement precision
If the absorption coefficient is not precisely controlled, then manufacturing is easier, but heating accuracy deteriorates
Solution Approach 1:
The patent specifies precise parameter ranges for free electron concentration (1×10^18 to 1×10^19 atoms/cm³) and absorption coefficient (1.2 to 48 cm⁻¹ at 2 μm wavelength) to achieve accurate heating. These parameter controls enable reproducible heating performance while maintaining manufacturability through defined doping concentration ranges.
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
Enables stable and uniform heating of the substrate, improving crystallinity and reducing crystal strain, which in turn enhances the quality and consistency of semiconductor devices by accurately controlling temperature and impurity concentrations.
Implementation Method 1
an absorption coefficient α is approximately expressed by equation (1) in a wavelength range of at least 1 μm or more and 3.3 μm or less: α=nKλa (wherein, λ(μm) is a wavelength, α(cm−1) is absorption coefficient of the nitride crystal substrate at 27° C., n (cm−3) is a free electron concentration in the nitride crystal substrate)
Data Source
AI summary
There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient α is approximately expressed by equation (1) in a wavelength range of at least 1 μm or more and 3.3 μm or less: α=n Kλa (1) (wherein, λ(μm) is a wavelength, α(cm−1) is absorption coefficient of the nitride crystal substrate at 27° C., n (cm−3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.5×10−19≤K≤6.0×10−19, a=3).