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In device-manufacturing technology, it is important to understand why dielectric films crack. With this objective in mind, we have constructed an apparatus for measurement of thermal stresses in thin films (25–500 °C), obtained results on various reactively plasma deposited (RPD) Si-N and CVD SiO2 films, and developed a model which quantifies the cracking resistance of different types of RPD Si-N films. Measurements were made of the coefficient of thermal expansion α (T), which increases on going from SiO2→Si3N4→SiN→Si and the intrinsic stress, which is compressive for RPD Si3N4, nearly zero for thermal SiO2 and tensile for RPD SiN and CVD SiO2. The cracking resistance of Si-N film at a given temperature is functionally related to its density, intrinsic stress, thermal mismatch with Si, and the deposition temperature.

Silicon dioxide films have been deposited by reacting silane and nitrous oxide in a parallel‐plate, radial flow, plasma reactor. Deposition parameters (temperature, power, and gas composition) have been systematically varied, and the films characterized by measuring the infrared spectra, deposition rate, density, etch rate, stress, refractive index, step coverage, breakdown voltage, and annealing behavior. The films, deposited at 100°–340°C and at rates of 200–360 Å/min, contain 2–9 a/o H bonded as H2O , normalSiOH , and normalSiH . The films have densities of about 2.3 g/cm3, refractive indexes of about 1.47, a compressive stress usually less than 1×109 normaldynes/cm2 , and etch rates about twelve times faster than thermally grown silicon dioxide. Films deposited below 200°C or at high power etch nonuniformly with part of the film etching very fast, possibly indicating a two‐phase mixture. The step coverage is not conformal and the films are thin along vertical step walls. The films breakdown at fields of 4–10 MV/cm. During annealing in air at temperatures up to 400°C, the films lose hydrogen and become less dense, but do not crack. The properties of the plasma‐deposited silicon dioxide are strongly dependent on the specific deposition conditions. In addition, simple correlations between the properties do not exist. Thus in characterizing plasma deposited silicon dioxide, the exact deposition conditions must be specified and all the film properties of interest must be measured.

Amorphous Si-N films have been synthesized from SiI~ and NI~ by reactive plasma deposition at 275~ in an improved radial flow reactor. With appropriate control of machine and process" variables, films have been made with Si/N ratio of 0.75-1.5, density of 2.8-2.2g cm -~, refractive index of 1.9-2.3, stress of 2 • l0 s dynes cm -2 compressive to 5 • 109 dynes cm -2 tensile, and electrical resistivity at 2 • 106 V/era of I0~~ ~-cm. The process is MOS compatible and it produces relatively thick (1 ~m) crack-resistant Si-N films (at 450~ having excellent step coverage and good adhesion to both Au and A1 metallization. This paper describes the deposition technique, effect

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