Articles you may be interested inHigh reflectivity dielectric mirror deposition by reactive magnetron sputtering J. Vac. Sci. Technol. A 10, 3305 (1992); 10.1116/1.577816Modeling reactive sputtering process in symmetrical planar direct current magnetron systems A comparison of SiO2 planarization layers by hollow cathode enhanced direct current reactive magnetron sputtering and radio frequency magnetron sputtering Reactively rf magnetron sputtered AlN films as gate dielectric Dielectric layers like A1 2 0 3 • Si0 2 , and Si)N4 have been produced by a reactive ac magnetron sputtering process, using a two cathode arrangement. Within a frequency range between 10 and 100 kHz, where the ions still completely follow the ac field, deposition rates comparable to the de case could be achieved. In contrast to dc sputtering above a certain frequency of some ten kHz no disturbing charges on dielectric parts of the target surface can build up, thus preventing the well-known problem of arcing. Above this frequency the probability of arcing decreases to zero, leading to a stable process. High deposition rates of about 40 A/s could be realized for the AI-and Si-based reactive processes. This was achieved by a control unit combining the discharge voltage and the reactive gas flow in order to stabilize the transition between the metallic and the dielectric sputter mode. In case of dynamic deposition a homogeneous film thickness distribution on a substrate area of 350X450 mm 2 of better than ±5% was obtained. An easy scale-up to bigger cathodes is expected due to the simple coupling of the ac power to the cathodes in this frequency range. The investigated dielectric layers are characterized by optical and mechanical measurements.

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SAMPLE Abstruct-Thisletter reports the properties of metal-nitride-Si (MNS) capacitors in which the silicon nitride layer is produced by the jet vapor deposition (JVD) technique at room temperature. Despite the room-temperature deposition, the electrical properties of these devices are far better than any previously reported MNS capacitors. Especially remarkable is the low density of interface traps (Dit < 5 X 10"/cm2 -eV near midgap). In addition, these MNS capacitors are highly resistant to damage caused by hot electrons and ionizing radiation. He + 'IH4 No NOZZLE ET vapor deposition (JVD) is a new technique [l], [2] J for preparing thin films of metals, semiconductors, dielectrics, and organics [3]-[6]. In JVD, a nozzle forms a supersonic jet of inert carrier gas that transports vapor to stationary [2] or moving [l] substrates. The vapor can be generated by thermal evaporation, sputtering, or microwave discharge inside the nozzle. The advantages of JVD compared to other techniques have been stated in [3]-[6]. In this letter we present recent results on the properties of metal-nitride-Si (MNS) capacitors in which the silicon nitride layer is produced by JVD at room temperature.Silicon nitride deposition is carried out with the coaxial nozzle jet vapor source shown in Fig. 1. Highly diluted silane from the inner nozzle and N, from the outer nozzle flow into a helium microwave discharge sustained near the outer nozzle exit. Reactive Si species and N atoms generated in the discharge are carried by the sonic He jet toward the substrate where they form silicon nitride.Substrate preparation is an important factor. The best films are deposited on Si substrates that underwent an in-situ H plasma etching (using the same jet arrangement) prior to nitride deposition to remove the native oxide and other contaminants. The deposition rate is controlled by the SiH,/He ratio and the flow rate, which critically CHAMBER WALL E W N Fig. 1. Schematic diagram of plasma-assisted jet vapor source for nitride deposition. The inner nozzle contains 20 ppm of SiH, in He at a pressure of 600 torr; the outer nozzle contains He, ", gas at a pressure of 2 torr; the deposition chamber is maintained at 0.5 torr.affects the film properties. The best films are produced at a very low deposition rate of N 15 A/min, which arises from a highly diluted SiH, gas ( -10 ppm of SiH, in He) at an inner nozzle pressure of 600 torr. The SiH, gas is further diluted by the He/N, gas coming from the outer nozzle before entering the deposition chamber, which is maintained at 2 torr. Under these deposition conditions, the nitride film exhibits an index of refraction (at h = 6328 A) of about 2.03, which is close to the value for stoichiometric Si,N,, and an etch rate of approximately 10 A/min in BOE.After the nitride deposition is complete, 2000 A of aluminum is evaporated. Aluminum gate electrodes are photolithographically defined; this is followed by back-side metallization and annealing in forming gas at 400°C for 1 h. It should be noted that no other annealin...

A differential mobility analyzer for high-mobility resolution (1/FWHM$30) classification of 1-67 nm particles is designed to analyze viral particles. Inner and outer electrode radii of 1.01 and 2 cm (at the outlet slit) and a 11.6 cm long column achieve this range at a sheath gas flow (Q) and aerosol flow (q) of 30 and 1 L/min. Turbulent transition potentially resulting from this substantial length combined with high sheath gas flow rates (Q$1000 Lit/min) required to classify 1 nm particles is avoided by stabilizing the flow via a continuous acceleration with a conical inner electrode (1 half-angle). High axisymmetry of the aerosol flow as it joins the sheath gas is achieved by injecting it through a circularizer ring with 24 symmetrically spaced orifices. The sheath flow is laminarized with two pre-laminarization schemes, three laminarization screens, and an inlet trumpet with an area $3 times the analyzer channel throat area. The instrument is tested with singly charged monomobile cluster ions produced by a bipolar electrospray source. A resolving power of 29 is measured at the highest flow rate reached, with a trend towards even higher resolution if either Q or the monomobile particle size could be increased. This performance indicates that the electrode concentricity is excellent and the flow highly stable. Tests carried out at limited resolution (set below 16 by a protein test aerosol) with the modest Q/q$30 values required to classify 70 nm particles indicate that the DMA response is close to ideal at Q ¼ 151, 110, and 47 Lit/min.

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