HPHT Single Crystal Diamond Growth Using {110} Seed Orientation
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Solution Overview
Problem
Conventional methods for producing large single crystal diamonds face challenges in achieving high quality, uniform optical properties, and desired crystallographic orientations, leading to inefficiencies in material utilization and increased processing costs due to size and shape limitations, as well as issues with inclusion formation and hardware control failures.
Innovation Solution
A method involving the selection of a single crystal diamond seed with a {110} growth surface and specific aspect ratio, mounted on a substrate, and grown in a high-pressure high-temperature environment within a controlled temperature range to produce diamonds with enhanced abrasion resistance and tailored morphology, allowing for minimal processing and increased material utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional HPHT methods are used to grow large single crystal diamonds, then crystal size can be increased, but manufacturing precision and uniformity of optical properties deteriorate due to inclusion formation and growth sector variations
Solution Approach 1:
The patent applies local quality by selecting a specific growth sector ({110} sector) that has superior optical properties and lower nitrogen solubility compared to other sectors. By orienting the seed crystal to grow predominantly in this sector, the resulting diamond exhibits uniform optical properties throughout the crystal structure, even at large sizes. This resolves the contradiction by ensuring that the entire crystal volume maintains consistent quality characteristics.
Solution Approach 2:
The patent changes the growth parameters by controlling the temperature gradient and pressure conditions to favor growth in the {110} sector. By adjusting these physical parameters, the growth rate and quality characteristics are optimized to produce large crystals with uniform optical properties, preventing inclusion formation that typically occurs in other growth sectors.
2Shape
If temperature is used to tune crystal morphology, then crystal shape can be modified, but the extent of tuning is limited and cannot achieve desired cubic or octahedral forms
Solution Approach 1:
The patent changes the crystallographic orientation parameter by selecting seeds with specific orientations ({110}, {100}, or {111} sectors) to control the final crystal morphology. This approach provides versatile control over crystal shape, enabling the production of desired cubic or octahedral forms that cannot be achieved by temperature tuning alone. The seed orientation directly determines the growth sector and final crystal habit.
3Reliability
If seed crystals are retained in ceramic carriers during growth, then seed position can be maintained, but crystal growth is restricted to half the solid angle and processing complexity increases
Solution Approach 1:
The patent extracts or removes the ceramic carrier from the final crystal structure by designing the growth process so that the carrier does not interfere with the crystal growth geometry. This allows the crystal to grow into the full solid angle without being constrained by the carrier, while still maintaining seed position stability during the growth process. The carrier is either removed after growth or designed to minimize its impact on crystal morphology.
4Volume of moving object
If synthesis cycle time is extended to produce suitably sized material, then crystal size can be achieved, but productivity decreases and risk of hardware control failure increases
Solution Approach 1:
The patent changes the pressure and temperature parameters to optimize the growth rate while maintaining crystal quality. By operating at optimized HPHT conditions, the synthesis time is reduced, allowing larger crystals to be produced in shorter cycles. This increases productivity and reduces the risk of hardware control failures while achieving the required crystal sizes for tool 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 method enables the production of high-quality single crystal diamonds with large dimensions and tailored crystallographic orientations, reducing processing needs and increasing synthesis efficiency, resulting in diamonds suitable for tool applications with improved abrasion resistance and reduced material waste.
Implementation Method 1
effecting crystal growth in a high pressure high temperature environment at a temperature in the range from 1280°C to 1390°C under conditions such that a single crystal diamond is produced on at least the growth surface of the seed
Implementation Method 2
synthesis of diamond by the temperature gradient HPHT method
Data Source
Figure 1a~1f
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
A high pressure high temperature (HPHT) method for synthesizing single crystal diamond, wherein a single crystal diamond seed having an aspect ratio of at least (1) and a growth surface substantially parallel to a {110} crystallographic plane is utilised is described. The growth is effected at a temperature in the range from 1280°C to 1390°C.