The electrical properties of Si3N4/SiO2/Si structures, which are currently used in integrated circuits technology, are largely dependent upon the structure and the chemical composition of the interface regions which may be a few Å thick. Such locked-in regions are difficult to analyze by destructive techniques like secondary ion mass spectroscopy (SIMS) or Auger electron spectroscopy (AES) with ion milling. We show that spectroscopic ellipsometry, operating in the 1.5–6 eV range, is capable of nondestructively analyzing the interface region. The method is demonstrated on standard atmospheric pressure chemical vapor deposition (CVD) nitride layers and the results are compared with ion-milling AES data. The effects of O2 annealing and NH3:SiH4 ratios are also investigated.

Silane is the main gas used in the field of electronics to produce compounds of silicon. The direct analysis of silane by inductively coupled plasma mass spectrometry has been found to be a practical proposition for both the measurement and indentification of elemental impurities at the su b-parts per billion level. Several steps, however, need to be taken to optimise commercial instrumentation further for this task. Firstly, in order to minimise the amount of matrix material being deposited on the sampler orifice, an alloy sample cone was used which operated at a higher temperature than that of the commercially available nickel cones; additionally, the optimum carrier gas flow-rate with silane was found to be significantly lower than that required to achieve maximum sensitivity in argon alone. This too reduced sample deposition around the orifice. A further increase in sensitivity was achieved when the argon carrier gas was supplemented by the addition of hydrogen; the detection limits for 75As and 1271 were 0.55 and 0.65 p.p.b., respectively, with a precision of 2-5%. In order to quantify impurities in the silane two techniques were employed. The first used the silicon matrix as an internal standard and the second involved direct comparison with a calibration graph obtained by the addition of impurities to the silane.

Growth oscillations with monolayer periodicity monitored by ellipsometry during metalorganic vapor phase epitaxy of GaAs (001) Continuous transition from multiple quantumwell regime to superlattice regime in GaAlAs/GaAs system as observed by spectroscopic ellipsometry with high lateral resolution

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