INFLUENCE DE LA TECHNIQUE DE PREPARATION ET DE LA TEMPERATURE DE MESURE SUR LES PROPRIETES OPTIQUES DES COUCHES MINCES DE SILICIUM AMORPHE

Les propriétés optiques de couches minces de silicium amorphe déposées par décomposition en phase vapeur et décharge luminescente du silane ou par pulvérisation cathodique radiofréquence sont déterminées à partir des mesures de la transmission et du pouvoir réflecteur dans un domaine d'énergie compris entre 0,5 et 5,5 eV. Les mesures sont faites à diverses températures comprises entre 95 et 723 K. Quelle que soit la technique de dépôt lorsque la température de mesure Tm devient supérieure à la température du substrat Ts des variations irréversibles du gap optique Eg (Tm) et de l'indice de réfraction no (Tm) se produisent. Dans le domaine de température étudié no (Tm) varie linéairement avec Eg (Tm) ; la pente de la droite décroît linéairement avec la concentration en hydrogène. Quelle que soit la technique de dépôt et la façon dont l'hydrogène s'incorpore dans la matrice de silicium la concentration en hydrogène semble être le facteur prépondérant dans la façon dont varie l'indice de réfraction statique avec le gap optique.Optical properties of amorphous silicon films prepared by chemical vapor deposition, glow discharge and sputtering RF were determined from reflectance and transmittance measurements in the energy range 0.5 to 5.5 eV. The measurements were done at various temperature Tm in the range 95 to 723 K. Whatever the deposition technics when Tm becomes higher than Ts (substrate temperature) irreversible variations occur for both optical gap Eg (Tm) and static refractive index no (Tm). In the Tm range no (Tm) varies linearly with Eg (Tm) ; the slope of the straight line decrease linearly with hydrogen concentration. Whatever the deposition technic and the manner of incorporation of hydrogen in the Si matrix, hydrogen concentration seems to be the preponderant parameter between static refractive index and optical gap

EFFECT OF TEMPERATURE ON OPTICAL PROPERTIES OF GLOW DISCHARGE HYDROGENATED AMORPHOUS SILICON FILMS

Optical properties of hydrogenated amorphous silicon films, prepared by glow discharge onto fused quartz substrates held at temperature TS varying between 50 and 350°C, were determined from near normal specular reflectance and transmittance measurements in the energy range 0.5 to 5.5 eV. The measurements were done at various temperature Tm in the range 95 to 750 K. When Tm becomes higher than TS, irreversible variations of optical gap appear. An interpretation in terms of an hydrogen evolution and a rearrangement of the matrix under annealing is proposed

Temperature Effects On The Optical Properties Of Amorphous Hydrogenated Silicon Nitrogen Alloys Prepared By Rf Sputtering

Amorphous hydrogenated silicon nitrogen alloys with variable nitrogen concentration were prepared by the reactive RF sputtering method. The optical gap shows a drastic increase at an atomic N/Si ratio near unity. The variations of the optical gap and static refractive index were measured at different temperatures and after several heat treatments. Irreversible effects related to hydrogen evolution and changes in the microscopic structure were observed, the importance of which depends on the nitrogen concentration. © 1987 Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division).943353364Kurata, Hirose, Osaka, Wide Optical-Gap, Photoconductive a-SixN1-x:H (1981) Japanese Journal of Applied Physics, 20, p. L811Watanabe, Katoh, Yasui, Properties of Amorphous Films Prepared from SiH4-N2-H2Gas Mixture (1982) Japanese Journal of Applied Physics, 21, p. L341Lucovsky, Yang, Chao, Tyler, Czubatyj, (1983) Phys. Rev. B, 28, p. 3234Knolle, Osenbach, (1985) J. Appl. Phys., 58, p. 1248Chaussat, Bustarret, Deneuville, Chemical heterogeneity in off stoichiometry a-SixNyHz from a collective vibrational modes study (1985) Journal of Non-Crystalline Solids, 77-78, p. 917Chayahara, Ueda, Hamasaki, Osaka, (1985) Jap. J. Appl. Phys., 24, p. 19Tessler, Alvarez, (1986) J. Non-Cryst. Solids, 83, p. 1Osenbach, Knolle, (1986) J. Appl. Phys., 60, p. 1408Sasaki, Kondo, Fujita, Sasaki, (1982) Jap. J. Appl. Phys., 21, p. 1394Makino, Composition and Structure Control by Source Gas Ratio in LPCVD SiN[sub x] (1983) Journal of The Electrochemical Society, 130, p. 450Pan, Berry, (1985) J. Electrochem. Soc., 132, p. 3001Chaussat, Bustarret, Bruyere, Roleau, (1985) Physica, 129 B, p. 215Tsu, Lucovsky, Silicon nitride and silicon diimide grown by remote plasma enhanced chemical vapor deposition (1986) Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 4, p. 480Shimizu, Oozora, Morimoto, Kumeda, Ishii, (1982) Sol. Energy Mater., 8, p. 311Meaudre, Tardy, (1983) Sol. St. Commun., 48, p. 117Karcher, Ley, Johnson, Electronic structure of hydrogenated and unhydrogenated amorphous SiN_{x} (0≤x≤1.6): A photoemission study (1984) Physical Review B, 30, p. 1896J.I. Cisneros, H. Dias da Silva, M. Pereira and F. das Chagas Marques, Solar Energ. Mat., to be publishedMorimoto, Tsujomura, Kumeda, Shimizu, (1985) Jap. J. Appl. Phys., 24, p. 1394Lanford, Rand, (1978) J. Appl. Phys., 49, p. 2473Tsu, Lucovsky, Mantini, (1986) Phys. Rev. B, 33, p. 7069Carson, Schnatterly, (1986) Phys. Rev., 33 B, p. 2432Maeda, Nakamura, (1985) J. Appl. Phys., 58, p. 484M. Meaudre and R. Meaudre, Phi. Mag., to be publishedSample preparation and IR characterisation were made in the Institute of Physics, UNICAMPfor more details see ref. 17Bertrand, (1982) Thesis, , Montpellier, FranceDivrechy, Yous, Berger, Ferraton, Robin, Donnadieu, (1982) Thin Solid Films, 78, p. 235Leveque, (1979) Thesis, , Montpellier, FranceTauc, (1976) Amorphous and Liquid Semiconductors, p. 159. , Ch. 4, J. Tauc, Plenum, RigaWemple, Didomenico, (1971) Phys. Rev. B, 3, p. 1338Donnadieu, Yous, Berger, Ferraton, Robin, (1981) J. de Phys., 42, pp. C4-C655Berger, (1985) Thesis, , Montpellier, FranceZuther, Hubner, Rogmann, (1979) Thin Solid Films, 61, p. 391Hasegawa, Matuura, Kurata, (1986) Appl. Phys. Lett., 49, p. 127