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The composition, bonding configuration, hydrogen content, and paramagnetic defects of SiO[sub x]H[sub y] thin films were studied. Films were deposited by the electron cyclotron resonance plasma method at room temperature using SiH[sub 4] and O[sub 2] as precursor gases. The film composition was measured by heavy ion elastic recoil detection analysis and energy dispersive x-ray spectroscopy. Suboxide films with compositions ranging from SiO[sub 2] to SiH[sub 0.38] were obtained. Infrared spectroscopy showed the presence of different Si–O and Si–H vibration modes. The usual estimation of the oxygen to silicon ratio by the wave number of the Si–O–Si stretching band was not accurate for films far from stoichiometry. These off-stoichiometric films also showed a broader Si–O–Si stretching peak than the stoichiometric ones, indicating a higher bonding disorder. The position of the Si–O–Si bending and rocking modes did not depend on the film composition. On the other hand, the peak position of the Si–H modes were found strongly dependent on the Si environment. By single-wavelength ellipsometry at λ=632.8 nm the refractive index n was found to range between 1.45 (SiO[sub 2]) and 2.04 (SiO[sub 0.06]H[sub 0.36]). Electron spin resonance measurements showed that stoichiometric films presented the well known E[sup ′] center (·Si≡O[sub 3]) with concentrations in the 10[sup 16]–10[sup 17] cm[sup -3] range, while for Si-rich films (x<1) the Si dangling bond center (Si[sub DB], ·Si≡Si[sub 3]) was the only detectable defect, with concentrations in the 10[sup 18]–10[sup 19] cm[sup -3] range. In near-stoichiometric films both E[sup ′] and Si[sub DB] centers were found. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

SiO[sub x]N[sub y]H[sub z] films were deposited from O[sub 2], N[sub 2], and SiH[sub 4] gas mixtures at room temperature using the electron cyclotron resonance plasma method. The absolute concentrations of all the species present in the films (Si, O, N, and H) were measured with high precision by heavy-ion elastic recoil detection analysis. The composition of the films was controlled over the whole composition range by adjusting the precursor gases flow ratio during deposition. The relative incorporation of O and N is determined by the ratio Q=[lowercase_phi_synonym](O[sub 2])/[lowercase_phi_synonym](SiH[sub 4]) and the relative content of Si is determined by R=[[lowercase_phi_synonym](O[sub 2])+[lowercase_phi_synonym](N[sub 2])]/[lowercase_phi_synonym](SiH[sub 4]) where [lowercase_phi_synonym](SiH[sub 4]), [lowercase_phi_synonym](O[sub 2]), and [lowercase_phi_synonym](N[sub 2]) are the SiH[sub 4], O[sub 2], and N[sub 2] gas flows, respectively. The optical properties (infrared absorption and refractive index) and the density of paramagnetic defects were analyzed in dependence on the film composition. Single-phase homogeneous films were obtained at low SiH[sub 4] partial pressure during deposition; while those samples deposited at high SiH[sub 4] partial pressure show evidence of separation of two phases. The refractive index was controlled over the whole range between silicon nitride and silicon oxide, with values slightly lower than in stoichiometric films due to the incorporation of H, which results in a lower density of the films. The most important paramagnetic defects detected in the films were the K center and the E[sup ′] center. Defects related to N were also detected in some samples. The total density of defects in SiO[sub x]N[sub y]H[sub z] films was higher than in SiO[sub 2] and lower than in silicon nitride films. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

MIS structures have been fabricated on Si (111) by a two-step process: first an exposition of the Si substrates to an ECR oxygen plasma was performed, which yields a layer of SiOx (in the following PO-SiOx); this process was followed by an ECR plasma silicon nitride deposition (SiN1.55:H). The resulting MIS structure is Al/SiN1.55:H/PO-SiOx/Si. Devices have been characterized by the simultaneous measurement of the capacitance at high and low frequencies. This measurement lets us know the PO-SiOx/Si interface quality, calculate the thickness of the PO-SiOx layer and the growth rate of SiN1.55:H. To characterize the oxidation process some series of samples were prepared. In each series a process parameter was varied. These parameters were: the SiN1.55:H deposition time, the ECR plasma oxidation duration, the substrate temperature and the total oxygen flux. The bonding structure of the stacked dielectric has been studied by infrared spectroscopy. The stacked dielectrics spectra showed the superposition of two peaks: a less intense peak associated to the PO-SiOx layer with its maximum in 1056 cm-1, and another one due to the SiN1.55:H film with its maximum in 860 cm-1. These measurements showed that the PO‑SiOx growth law is dSiO = 2.7 tox 0.26 nm where dSiO is the PO-SiOx layer thickness and tox is the oxidation time in min. Concerning electrical characteristics, stacked MIS devices showed interface trap density minimums (Dit) close to 1011 eV-1cm-2. This value is inferior to the one that non-oxydized devices (Al/SiN1.55:H/Si) show. Also, stacked devices presented higher Fermi level sweeps and an electrical hysteresis almost insignificant.Se han fabricado estructuras MIS sobre Si (100) mediante un proceso en dos pasos: una primera exposición del sustrato de Si a un plasma ECR de oxígeno, que da lugar a la obtención de una capa de SiOx (en adelante PO-SiOx), seguido de un depósito de nitruro de silicio (SiN1.55: H) mediante plasma ECR. La estructura MIS resultante es de la forma Al/SiN1.55:H/PO‑SiOx/Si. Los dispositivos han sido caracterizados mediante la medida simultánea de las capacidades a alta y baja frecuencia, lo que permite conocer la calidad de la intercara PO‑SiOx/Si, calcular los espesores de la capa de PO‑SiOx y la velocidad de crecimiento del SiNx:H. Para caracterizar el proceso de oxidación se realizaron varias series de muestras variando en cada una un parámetro del proceso. Estos parámetros fueron: el tiempo de depósito del SiNx:H, el tiempo de oxidación, la temperatura del sustrato y el flujo total de O2. Asimismo, se ha estudiado la estructura de enlaces del dieléctrico apilado mediante espectroscopia infrarroja. El espectro del dieléctrico apilado mostró la superposición de dos picos: uno de menor intensidad asociado al PO‑SiOx con el máximo en 1056 cm-1, y otro debido al SiN1.55:H con máximo en 860 cm-1. Estas medidas mostraron que la ley que rige el crecimiento del PO‑SiOx es dSiO = 2.7 tox 0.26 nm donde dSiO es el espesor de la capa de PO-SiOx y tox es el tiempo de oxidación en min. Por lo que respecta a las características eléctricas, las estructuras presentaron mínimos de la densidad de trampas en la intercara (Dit) cercanos a 1011 eV-1cm-2. Este valor es inferior al que presentaron las estructuras sin oxidar, del tipo SiN1.55:H/Si. Además, los dispositivos apilados mostraron un barrido del nivel de Fermi mayor y una histéresis prácticamente despreciable.