III-V Semiconductor Substrate Surface Oxygen Doping
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Solution Overview
Problem
Current IIIA-VA group semi-conductor single crystal substrates face challenges in achieving high electron mobility and controlled oxygen content within a specific depth from the surface, as existing methods result in uniform oxygen distribution that can negatively affect the crystal structure and overall integrity.
Innovation Solution
A method involving placing a single crystal substrate in a sealed container and heat-treating it within a specific temperature range to achieve an oxygen content of 1.6×10^16-5.6×10^17 atoms/cm^3 and an electron mobility of 4,800 cm^2/V·s to 5,850 cm^2/V·s within a 10 μm depth from the surface, using techniques like Vertical Gradient Freeze and Liquid-Encapsulated Czochralski for GaAs, InP, or GaP substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Ga2O3 or As2O3 is added into GaAs charge and Liquid-encapsulated Czochralski or Vertical Gradient Freeze methods are used for growing the crystal, then oxygen content in the crystal is increased, but oxygen disperses uniformly throughout the crystal which negatively affects the crystal structure
Solution Approach 1:
The patent applies local quality by concentrating oxygen doping only in the surface region (0-10 μm depth) rather than uniformly throughout the entire crystal. This is achieved through specific heat treatment processes that introduce oxygen selectively to the surface layer, maintaining high oxygen content (1.6×10^16-5.6×10^17 atoms/cm³) in the surface while keeping the bulk crystal structure intact and free from uniform oxygen dispersion damage.
2Reliability
If impurities are introduced during single crystal material production to change electron mobility, then electron mobility is adjusted, but overall integrity of the single crystal material is adversely affected
Solution Approach 1:
The patent implements local quality by introducing oxygen impurities only in the surface region (0-10 μm depth) through controlled heat treatment, rather than throughout the entire crystal. This localized doping achieves the desired electron mobility (4,800-5,850 cm²/V·s) in the active surface region while preserving the overall integrity and low impurity content of the bulk single crystal material.
Solution Approach 2:
The patent applies partial action by introducing oxygen only to the extent needed in the surface region (1.6×10^16-5.6×10^17 atoms/cm³), rather than uniformly throughout the crystal. This partial doping achieves the required electron mobility adjustment in the active surface layer without excessive impurity accumulation that would damage the overall crystal integrity.
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 enhances the oxygen content and electron mobility within the specified depth, allowing for improved electrical properties and selective control of oxygen doping, addressing the limitations of existing substrate preparation techniques.
Implementation Method 1
A method involving placing a single crystal substrate in a sealed container and heat-treating it within a specific temperature range to achieve an oxygen content of 1.6×10^16-5.6×10^17 atoms/cm^3 and an electron mobility of 4,800 cm^2/V·s to 5,850 cm^2/V·s within a 10 μm depth from the surface
Data Source
AI summary
A IIIA-VA group semi-conductor single crystal substrate (2) has one of or both of the following two properties: an oxygen content of 1.6×1016-5.6×1017 atoms/cm3 in a range from the surface to a depth of 10 μm of the wafer, and an electron mobility of 4,800 cm2/V·s-5,850 cm2/V·s. Further, a method for preparing the semi-conductor single crystal substrate (2) comprises: placing a single crystal substrate (2) to be processed in a container (4); sealing said container (4), and keeping said single crystal substrate (2) to be processed at a temperature in the range of from the crystalline melting point −240° C. to the crystalline melting point −30° C. for 5 hours to 20 hours; preferably, keeping a gallium arsenide single crystal at a temperature of 1,000° C. to 1,200° C. for 5 hours to 20 hours.