PAM-XIAMEN can offer metallized diamond heat sink for solving the poor bonding force between diamond and the matrix and the early falls of the diamond due to high interface energy with most metals, ceramics, etc. A metallized diamond heat sink compound refers to plating metal on the diamond surface to reduce the interface energy between the diamond and the substrate. Here is a metallized diamond heat sink datasheet for reference.
1. Specification of Metallized Diamond Heat Sink
| Product | Metallized Diamond Heat Sink |
| Growth Method | MPVCD |
| Thermal Expansion Coefficient | 1.3(10-6K-1) |
| Thermal Conductivity TDTR Detection Method | 1500±200W/m.K |
| Size | 1*1 cm, 2*2 cm, custom sizes |
| Thickness Can Be Customized | Diamond 0~500μm |
| Thickness Tolerance | ±20μm |
| Growth Surface Roughness | < 30 nm Ra |
| FWHM(D111) | 0.446 |
2. How to Obtain the Metallized Diamond Heat Sinks?
Metal-semiconductor contacts are one of the core structures of all semiconductor electronic devices and optoelectronic devices, including semiconductor diamond devices. They can be divided into two categories: Schottky contacts and ohmic contacts. Ohmic contact requires the interface contact resistance to be as small as possible. The ohmic contact of semiconductor diamond is difficult to achieve, which is related to the difficulty of forming heavy doping on the diamond surface layer. Schottky contact requires high interface barrier, low leakage current, and high breakdown voltage.
2.1 Ohmic Contact of N-type Diamond
The ohmic contact of n-type diamond for heat sink uses 30 keV of Ga ions to bombard n-type diamond with a phosphorus doping concentration of 3×1018 cm3 to obtain a contact resistance of 4.8×106Ω/c㎡. So far, the lowest value of ohmic contact resistance of n-type semiconductor based on CVD diamond heat sink is 10-3Ω/c㎡, which is obtained by depositing a Pt/Ti metal layer on a heavily doped (phosphorus concentration of 1020cm³) diamond epitaxial layer and annealing.
2.2 Oxygen Terminal P-type Diamond
The metal/diamond interface barrier is closely related to the surface characteristics. Most of the research in this area by PAM-XIAMEN focuses on the diamond(100). The Schottky barrier height of the clean surface and the hydrogen-terminated diamond surface is related to the electronegativity or work function of the metal. Au is currently the most commonly used ohmic contact metal material for the hydrogen-terminated diamond surface p-type layer. The Fermi level of the oxygen-terminated p-diamond (100) is pinned at about 1.7eV above the valence band. The metal/diamond interface barrier has little relationship with the metal type, and the experimental report value is 1.5-2eV.
The barrier height of the oxygen-terminated diamond(111) surface is basically independent of the contact metal, and the experimentally reported value is about 1eV. The ohmic contact of oxygen-terminated p-type diamond generally selects metals that can form carbides with diamond at high temperatures, such as Ti, Mo, etc. They can form TiCx, MoCx and other carbides with diamond at high temperatures, leading to a narrow interface states or a decrease in barrier height. Another way to make diamond ohmic contacts is high-energy ion implantation, which causes lattice damage on the surface of the contact area. Currently, the contact resistance of Ti/p diamond (with a boron concentration of 1018cm3) obtained by heat treatment is less than 10-6Ω/c㎡.
3. Application of Metallized Diamond Heat Sink
Metallized polycrystalline/synthetic diamond heat sink can be used for power electronic devices and solid microwave power devices, greatly improving the working power and working temperature.
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