UV-CVD deposited SiNH films on InP: Optimization of the physico-chemical and interface properties
✍ Scribed by M. Petitjean; N. Proust; J. -F. Chapeaublanc; J. Perrin
- Publisher
- Springer
- Year
- 1992
- Tongue
- English
- Weight
- 436 KB
- Volume
- 54
- Category
- Article
- ISSN
- 1432-0630
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✦ Synopsis
High quality silicon nitride films are deposited at low temperature on InP substrates by direct photolysis at 185nm of a NH3-SiH4 gas mixture. The composition of the films is measured by nuclear analysis. The thickness and refractive index are obtained by ellipsometry at 632.8nm. As-deposited and post annealed samples are electrically characterized: quasi-static I(V) at 5 x 10 -4 Hz and C(V) characteristics at 1 MHz are performed on InP MIS diodes structures in order to optimize bulk and interface properties. At 250°C and 4 Torr, it is found that the highest critical field (measured for a leakage current density of 10 -9 A/cm a) is obtained for the injected ratio [SiH4]/[NH3] = 2%. For these conditions, the film is stoichiometric, the critical field is 4 MV/cm and the resistivity is 6 x 1015 f~cm. The interface state density (Nss) on InP is deduced from Terman analysis. The annealing conditions and the surface cleaning of InP have been optimized in order to reduce the Nss which is, for our best conditions, as low as 2 x 1011 eV -1 cm -2.