Silicon dioxide films were deposited in a parallel-plate electrode RF plasma-enhanced chemical vapor deposition (PECVD) system using hydrogen-free tetraisocyanatesilane (TICS) and oxygen. The deposition parameters were varied systematically, and the films were characterized by measuring infrared spectra, density, etch rate, refractive index, and current-voltage (I–V) and capacitance-voltage (C–V) characteristics, as well as by examining their annealing behavior. At 300°C and a TICS partial pressure ratio of 20%, a water-free and hydroxyl-group-free SiO2 film was obtained. The film density, BHF etch rate, refractive index, resistivity, and dielectric constant were 2.3 g/cm3, 330 nm/min, 1.46, 7×1015 Ω·cm, and 3.6, respectively. The film quality degraded and, simultaneously, the film absorbed moisture from the atmosphere with decreasing deposition temperature; however, the quality can be improved by reducing TICS partial pressure. SiO2 films could be deposited even at 15°C, and had a resistivity of about 1013Ω·cm. Infrared measurements showed that SiO2 films deposited from TICS/O2 contained less absorbed water than those deposited from hydrogen-containing source materials at the same deposition temperature.

Small-dimension photonic devices for telecommunications applications have recently attracted increasing interest along with the development of dry etching techniques. Extremely accurate control of etching depth is often needed for the fabrication of these devices containing multiple quantum well (MQW) structures. The excellent anisotropy, reasonable etching rates and excellent compatibility with resist masks of reactive ion etching (RIE) permit this technique to be used for fabrication of such devices. A drawback of the technique is that it is difficult to control etched depth with an accuracy of the order of the QW dimension. Laser interferometry (reflectometry) (LIR) is a powerful method for in situ monitoring of MQW structure etching. End-point detection (EPD) with very high depth resolution is obtained by appropriately combining the operating parameters of RIE and of LIR acquisition.In this paper we discuss the use of LIR at 670 nm to monitor the etching of InP/InGaAs(P) MQW structures by CH 4 /H 2 /(Ar) RIE and we report the real-time monitoring for etching of a 0.5 nm thick InGaAsP layer embedded between InP layers which is, to the best of our knowledge, the highest resolution ever reported for this technique.In the MQW etching process, the use of LIR combined with RIE successfully detects all stack layers with a resolution better than the well/barrier thicknesses. This capability permits etching to be monitored with well thickness as small as 3 nm in the case of InP/InGaAs layers. For structures having well/barrier layers with similar composition and hence a small refractive index difference, such as two In 1−x Ga x As y P 1−y layers with y = 0.57 and y = 0.84 respectively, monitoring of the etching of MQW with well thicknesses as small as 5 nm is demonstrated.The technique illustrated in the paper also proved to be useful as a simple method of analysing structure layers: the sequence and the uniformity of the QWs can be characterized with very high resolution.

We have fabricated n-channel InSb MISFETs using SiO 2 films as gate insulators. The insulator was deposited by PECVD using tetra-isocyanate-silane (TICS) and oxygen (02) as source gases. Threshold voltage and carrier mobility at 77K were 0.5V and 4200cm2/Vs, respectively.

A fluorine-doped silicon dioxide (SiO2:F) film with dielectric constant as low as 3.0 was deposited by introducing trifluoroacetic anhydride ((CF3CO) 2O TFAA) into our hydrogen-free SiO2 PECVD system using tetraisocyanatesilane (Si(NCO)4 TICS) and O2. The film was deposited at 100°C and 0.5 Torr. It was annealed by in-situ, 0.2 Torr O2 plasma treatment at 400°C for 1 hour, as well as post-metallization annealing in N2 ambient at 400°C for 1 hour. The refractive index and the ratio of infrared absorbance of Si-F/Si-O-Si peak intensity were 1.37 and 11.7%, respectively. No peak related to water absorption was clearly observed in its infrared spectrum even after contact-holes opened and dipped into boiling water for 2 hours.