SiN x passivation films were deposited on carbon nanotube field-effect transistors (CNTFETs) by catalytic chemical vapor deposition (Cat-CVD) at low substrate temperatures. Deposition at 330°C induced many defects in the CNT channels. The measurement of electrical properties revealed that p-type CNTFETs were converted to n-type CNTFETs after deposition at 270°C. Air-stable p-type top-gated CNTFETs with SiNx passivation films deposited at 65°C were operated. Thus, Cat-CVD is highly suitable for depositing high-quality SiNx passivation films on CNTFETs and the fabrication of n- or p-type CNTFETs can be controlled by changing the deposition temperature of SiNx passivation films.

Silicon nitride (SiN x ) films on Si and poly(ethylene terephthalate) (PET) substrates were prepared at approximately 150 C by catalytic chemical vapor deposition (Cat-CVD), using a SiH 4 /NH 3 gas mixture. A water vapor transmission rate as low as 0.2 g/m 2 day and an O 2 gas transmission rate of 0.6 cm 3 /m 2 day were achieved for a stoichiometric Si 3 N 4 film of 77 nm thickness. Although these transmission rates depended on N/Si ratio, no optical absorption was observed under preferable deposition conditions.

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This article covers acoustic design from two main aspects: the design of acoustical devices such as microphones, loudspeakers, etc, and the principles for reduction of sound through partitions, in rooms, etc. These sections are preceded by a description of the behaviour of sound waves and vibrating bodies, and an outline of human response to sound. Finally, special problems in silencing and in the diagnostic use of sound are described. Acoustic design principlesVector velocity of element of source Absorption coefficient of a surface = p / p~, fraction of critical damping Angle of directivity of a dipole source Coefficient of resistive force in a vibrating system Value of p for critical damping of a vibrating system Frequencies of resonance in a rectangular room Density of air Phase lags in vibrating systems Angular frequency. 147 IntroductionThere are two main aspects to acoustical design. The first is concerned with the principles which can be applied to the practical realization of devices such as microphones, loudspeakers, etc, to enable them to work correctly: the second is concerned with the design of devices or structures to reduce noise. Since most problems of noise concern the human subject, the latter aspect of the work necessitates a knowledge of human reaction to noise.This paper deals only with acoustics in the audible region, approximately 20-20000 Hz. Ultrasonics is today virtually a technology on its own. both in communications and in 'sonics'-the term used for the application to engineering devices; while infrasonics (acoustical phenomena below the threshold of hearing) is beginning to develop.The first part of the paper deals with the behaviour of sound waves and the characteristics of random noise. Spectrum measurements and sound-level measurements are described, and human response to noise-ranging from annoyance, through speech interference, to damage to hearing-is outlined.The second part deals with the design of acoustical instruments such as microphones and loudspeakers; this is introduced by a section on the powerful technique of acoustical analogies.The third part deals with design from the point of view of the control of sound waves in auditoria and in transmission through partitions; anti-vibration methods are also described, and the section concludes with a brief review of special methods in silencing and in the diagnostic use of noise. Acoustic sources and fields 2.1. Magnitudes in acousticsOne of the problems in dealing with acoustics is that the physical quantities are so small. The often-quoted statement that the acoustical energy produced by the shouting of a Cup Final crowd would heat enough water to make a cup of tea is accurate enough; even the shouting voice produces an acoustic power of only milliwatts. Of course the aerodynamic energy-to say nothing of other forms of energy-in the process is vastly greater, but conversion efficiencies from aerodynamic to acoustical energy are in the region of 10-4 or 10-5 for many processes.It follows therefore that most acoustical measuremen...

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Silicon nitride (SiN x ) films were deposited on Si and polycarbonate (PC) substrates at temperatures below 100°C by a catalytic chemical vapor deposition (Cat-CVD) method. By adding H2 to source gases, SiH4 and NH3, it was possible to prevent the deterioration of film qualities in low-temperature deposition processes. H atoms produced from H2 are effective for increasing the film densities and improving passivation properties. The water vapor transmission rate of SiN x films on PC substrates deposited at 80°C was lower than 0.3 g/m2day; the detection limit for a cup method. It is concluded that the Cat-CVD method with H2 dilution is a promising technique for preparing highly moisture-resistive SiN x films at low temperatures.