Features of Manufacturing the Element Base of High-Temperature Electronics Using Laser Radiation
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-04-29 |
| Journal | Doklady BGUIR |
| Authors | E. Đ. Shershnev |
| Institutions | Francisk Skorina Gomel State University |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive Summaryâ- Core Technology: The research validates a Thermal Laser Separation (TLC) technique for the controlled, kerf-free cleavage of natural and synthetic diamond crystals, essential for high-temperature (HTE) and high-power electronic components.
- Mechanism: Cleavage is achieved by inducing localized, critical thermoelastic microstresses (CTM) through rapid heating (1064 nm laser) followed immediately by water aerosol cooling.
- Fracture Control: The process relies on the anisotropic elastic properties of diamond, ensuring controlled brittle fracture propagation along the crystallographic plane exhibiting the minimum surface energy, identified as the (111) plane (10.6 J/m2).
- Modeling Confirmation: Non-stationary thermal conductivity modeling confirmed that the maximum critical stress (Ï33) is localized 0.5-0.8 mm below the surface, enabling bulk cleavage initiation rather than surface cutting.
- Optimal Regime: Optimal separation was achieved using a diode-pumped 1064 nm laser operating in a quasi-continuous wave mode, with pulse frequencies between 1-15 kHz and pulse energies of 10-20 mJ.
- Manufacturing Advantage: This method allows for highly precise separation of diamond wafers (up to ~250 ”m depth) without material ablation or kerf loss, significantly improving yield and component geometry.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Laser Wavelength | 1064 | nm | Diode-pumped, quasi-CW operation |
| Laser Pulse Frequency | 1-15 | kHz | Optimal experimental range |
| Laser Pulse Energy | 10-20 | mJ | Optimal experimental range |
| Laser Pulse Duration | Up to 15 | ns | Optimal experimental range |
| Thermal Source Power Density (Modeling) | 2 · 106 | W/cm2 | Input for temperature/stress calculation |
| Processing Depth (Cleavage) | ~250 | ”m | Achieved depth of controlled separation |
| Critical Stress Localization Depth (Ï33) | 0.5-0.8 | mm | Depth where maximum thermoelastic stress forms |
| Diamond Melting Temperature (Tm) | 3700-4000 | °C | Reference material property |
| Brittle Fracture Temperature Threshold | ~0.37 Tm | °C | Temperature required for microdeformation |
| Minimum Surface Energy Plane | (111) | J/m2 | Cleavage plane (Value: 10.6 J/m2) |
| Youngâs Modulus (Ï11) | 1079 | GPa | Diamond elastic constant |
| Coefficient of Linear Expansion (α) | 1.1 · 10-6 | °C-1 | Used in thermoelastic stress calculation |
| Beam Diameter (Output Mirror, 0.1 Power Level) | 0.6 | mm | RL10Q laser specification |
| Beam Divergence | < 2.6 | mrad | RL10Q laser specification |
Key Methodologies
Section titled âKey Methodologiesâ- Initial Defect Creation: A preliminary micro-rupture point (microcrack) is intentionally formed on the diamond surface using a pulsed ablation laser. This defect acts as the stress concentrator necessary to initiate controlled cleavage.
- Thermal Modeling: Non-stationary, axisymmetric heat conduction equations were solved in cylindrical coordinates. The model calculated temperature distributions (T) based on a moving Gaussian heat source (Equation 2, using P0, scanning speed v, and absorption coefficient Îł).
- Thermoelastic Stress Calculation: Based on the calculated temperature fields, the magnitude and distribution of thermoelastic mechanical microstresses (Ïij) were determined using the formula derived from LamĂ© coefficients and linear expansion (Equation 3).
- Stress Localization: The modeling confirmed that the maximum critical stress (Ï33) required for cleavage is generated not at the surface, but in a localized CTM zone 0.5-0.8 mm deep within the crystal volume.
- Controlled Cleavage Process (TLC): The two-stage process involves:
- Heating: Applying a focused 1064 nm quasi-CW laser beam along the desired separation line.
- Cooling: Immediately applying a water aerosol stream (refrigerant) to the heated zone to induce rapid thermal gradients and generate the necessary tensile stress for crack propagation.
- Fracture Mechanics Application: The Griffiths criterion was applied, confirming that the crack propagates along the path of least resistanceâthe plane corresponding to the minimum free surface energy, which is the (111) crystallographic plane.
- Experimental Verification: Experiments were conducted using a modernized EM-260 setup with a RL10Q diode-pumped laser, verifying the modeled CTM zone formation and achieving controlled cleavage profiles (V-shaped cut profile, depth ~250 ”m).
Commercial Applications
Section titled âCommercial Applicationsâ- High-Temperature Electronics (HTE): Manufacturing of diamond-based substrates and active components (e.g., diodes, transistors) designed for operation in extreme thermal environments where silicon and GaAs fail.
- High-Power RF and Switching: Production of high-voltage and high-current devices, leveraging diamondâs superior electrical breakdown strength and thermal dissipation capabilities (high thermal conductivity).
- Acousto- and Optoelectronics: Precision dicing and shaping of diamond wafers for components used in picosecond optoelectronics and high-frequency acoustic devices.
- Kerf-Free Wafer Processing: Implementation in semiconductor manufacturing lines for high-yield, low-waste separation of synthetic diamond wafers, reducing material costs significantly compared to abrasive or ablative cutting methods.
- Anisotropic Component Fabrication: Customized processing of diamond elements requiring specific crystallographic orientations, utilizing the ability to control cleavage efficiency based on the chosen plane (e.g., (111) vs. (100)).
- Advanced Sensor Technology: Fabrication of robust, thermally stable components for detectors of elementary particles and other harsh environment sensors.
View Original Abstract
The paper presents the results of research on laser processing of natural and artificial diamond crystals in microelectronics technologies by thermal laser separation. An analysis of physical-chemical phenomena observed as a result of the thermal effect of laser radiation on anisotropic materials in various crystallographic directions is conducted. Based on the Griffiths criterion, the mechanics of brittle fracture as a result of the formation of critical micromechanical stresses caused by the thermal action of laser radiation are analyzed. The non-stationary problem of thermal conductivity was solved, temperature distributions in the volume of the material were calculated, on the basis of which information on the change of elastic properties of crystals leading to its controlled destruction in given directions was obtained. The simulation results were confirmed experimentally in the processes of thermal laser separation of rough diamonds by forming localized areas of critical thermoelastic microstresses at a given depth in the crystal volume, which are the starting point of the line of controlled crystal separation. Optimal modes of controlled separation of crystals of natural and artificial diamonds using a diode-pumped laser with a radiation wavelength of 1064 nm have been identified.