Some Results

— Highest CVD diamond
Model AX5000/AX5200
Model AX5250/AX5400
Model AX6550/6560
Model AX6600

From Model AX5000/5200

The AX5000 / AX5200 incorporate process development for the growth of high quality CVD diamond films for application in electronics, optics, thermal management, and tools. The AX5000 deposits CVD diamond on 2-in diameter substrates with good thickness uniformity substrates up to 4-in diameter can be accommodated.

Raman spectrum of a CVD diamond films	SEM of a diamond film
Diamond membrane approximately 2 mm thick (Membrane courtesy of Dr. H.dishmann, BP America, Inc.)

From Model AX5250/AX5400

The AX5400/AX5250 incorporate process development for the growth of highest quality CVD diamond films at very high growth rates. Uniform, free standing diamond materials for advanced applications are obtained.

SEM of a thick diamond film	Raman spectrum of a CVD diamond films
Examples of thick CVD Diamond films suitable for heat sink applications (the larger wafer is 2 in. diameter)

Diamond deposition at high power densities has yielded more than one-of-magnitude improvement of the linear growth rates previously possible in similar reactors at lower power densities. In this new system, diamond deposition rates of up to 60 mg/hour have been demonstrated. Linear growth rates of 15micro meter/hour near the center of the sample have been measured. Figure 1 shows a cross-section of a diamond film grown at such rates. Note the columnar structure characteristic of high growth rate depositions. Figure 2 shows a top view of the films. Nicely faced material is obtained. At these high rates, thick free-standing films are possible within a few hours of deposition.

Figure 3 shows preferential alignment of the crystals along the [100] direction which is obtained under some deposition conditions. Preferential alignment of the facets can have applications for these CVD films in active electronics.

The thermal conductivity of diamond films samples grown at rates near 3micro meter m/hour was measured using two different techniques. The measurements yielded values of the thermal conductivity in the 10 to 20 W/cm-K range. This high thermal conductivity value makes such films ideal for heat sink applications. As an example, the Raman spectrum for one of these films is shown in Figure 4. The FWHM of the diamond line near 1332cm-1 was measured at 6cm-1. This value is close to the width for natural diamond (approximately 2 cm-1). Such narrow width lines are characteristic of high quality CVD diamond.

Figure 1. SEM cross-section of diamond film
grown at 15micro meter per hour.

Figure 2. Surface of diamond film shown in
Figure 1.

Figure 3. SEM of diamond film grown at 5micro meter per hour, showing preferential [100] alignment.

Figure 4. Raman spectrum of typical diamond film

From Model AX6550/6560

AX6550/AX6560 are the reactors in a series that incorporates former ASTeX newest development in microwave reactor technology. The AX6550/AX6560 enable the user sufficient production capacity to capture a significant market share in the rapidly expanding thermal management and the highly competitive tool markets.

Advanced Materials

Seki microwave plasma CVD systems are now routinely used to deposit aligned carbon nanotubes (Figure 1), nanocrystalline diamond (Figure 2), and silicon carbonitride materials (Figure 3).

Figure 1.	SEM micrograph showing aligned carbon nanotubes grown by microwave plasma assisted CVD (Courtesy of L. C. Chen, National Taiwan University K. H. Chen, Academia Sinica)
Figure 2.	Example of micro and nano-crystalline diamond films grown in AX5000 (Courtesy of T. Soga, Nagoya Institute of Technology)
Figure 3.	Silicon Carbonitride (SixCyNx) crystals and aligned nano rods formed using microwave plasma (Courtesy of L. C. Chen, National Taiwan University K. H.Chen, Academia Sinica)

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