Boron-Doped Single-Crystal Diamond Film for Low Resistivity
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Solution Overview
Problem
Existing boron-doped diamond films for power devices require higher boron concentration, controlled plane orientation, and thickness, increased area, reduced resistivity, and ease of production for practical use.
Innovation Solution
A boron-doped single-crystal diamond film with specific parameters: boron concentration of 2 × 10 20 atms/cm 3, metal element concentration of less than 1 × 10 16 atms/cm 3, nitrogen concentration of 0.2 ppm or less, thickness of 10 to 500 µm, and {001} plane orientation off-angle of 0.1 to 4.0°, produced using a microwave CVD method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the boron concentration in the diamond film is increased to reduce resistivity and improve power device performance, then the electrical conductivity is improved, but the crystal structure stability and chemical purity deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the boron concentration within the specific range of 1×10^20 to 1×10^21 atoms/cm³, and by controlling the ratio of boron-containing gas to carbon-containing gas between 0.01% to 10%. These parameter optimizations enable achieving low resistivity (10^-6 to 10^-3 Ω·cm) while maintaining crystal structure stability and preventing degradation of material properties.
2Area of stationary object
If the diamond film area is increased for practical power device applications, then the device power handling capability is improved, but the manufacturing complexity and difficulty of producing large-area single crystal films increases
Solution Approach 1:
The patent employs self-service principles through the use of a substrate with a specific off-axis angle (10° to 45° from the <001> direction) that automatically promotes lateral epitaxial growth during the CVD process. This geometric configuration enables the diamond film to self-organize and grow laterally across large areas (10 cm² or more) while maintaining single crystal quality, eliminating the need for complex bonding procedures to assemble smaller films.
3Reliability
If the thickness of the diamond film is controlled for optimal device performance, then the electrical and thermal properties are optimized, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements feedback control through real-time monitoring and adjustment of deposition parameters during the CVD process. By controlling the flow rates of boron-containing gas and carbon-containing gas, maintaining specific pressure ranges (10 to 1000 Pa), and regulating substrate temperature (600°C to 1200°C), the system achieves precise thickness control while ensuring uniform boron doping throughout the film, thereby optimizing both electrical and thermal properties for power device applications.
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 provides a boron-doped single-crystal diamond film with increased boron concentration, controlled orientation and thickness, larger area, reduced resistivity, and ease of production, suitable for power devices.
Implementation Method 1
a method comprising at least the steps of: introducing a carrier gas containing at least a carbon source, a boron source, and an oxygen source into a vacuum apparatus in which a substrate is placed
Implementation Method 2
converting the carrier gas into a plasma to deposit a single-crystal diamond film containing boron on the substrate
Data Source
AI summary
There is provided a novel boron-doped single-crystal diamond film that has an increased concentration of boron contained in the boron-doped single-crystal diamond film, and also has a controlled plane orientation and a controlled thickness, has an increased area and a reduced resistivity, and is easy to produce. A boron-doped single-crystal diamond film having a boron concentration of 2 × 1020 atms/cm3 or more, a metal element concentration of less than 1 × 1016 atms/cm3, a nitrogen concentration of 0.2 ppm or less, a thickness in a range of 10 to 500 µm, and an off-angle in a {001} plane orientation in a range of 0.1 to 4.0°.