B. J. Hinds

Investigation of postoxidation thermal treatments of Si/SiO2 interface in relationship to the kinetics of amorphous Si suboxide decomposition

Interfacial Si suboxides (SiOx, x 500 °C initially there is a rapid segregation into amorphous Si (a-Si) surrounded by a SiO2 shell which acts as a diffusion barrier decelerating the reaction. Phenomenological modeling of kinetics with a one-dimensional Avrami–Erofe’ve treatment gives an upper limit for a-Si lateral growth rates of 1.2 A/s at 900 °C with an activation energy of 120 kJ/mol. PL, Raman, transmission electron microscopy and ellipsometry confirm this segregation model in the amorphous state. Due to the ra...

Minimization of suboxide transition regions at Si–SiO2 interfaces by 900 °C rapid thermal annealing

Transitions regions at Si–SiO2 interfaces contain excess suboxide bonding arrangements which contribute to interface roughness and also can give rise to electronically active defects. This article provides insights into the origin and temperature stability of these suboxide bonding arrangements by studying different interface formation processes, e.g., rapid thermal oxidation and plasma-assisted oxidation, and then subjecting these interfaces to rapid thermal annealing (RTA). The interfacial bonding chemistry has been studied before and after the RTA by Auger electron spectroscopy and it has been demonstrated that interfacial transition regions with suboxide bonding are a direct result of thermal and plasma-assisted oxidation at temperatures up to at least 800 °C, and that the excess suboxide bonding in interfacial transition regions is significantly reduced following a 30 s, 900 °C RTA. The kinetics of this interfacial annealing process are essentially the same as observed for the RTA-induced separation ...

Study of SiOx decomposition kinetics and formation of si nanocrystals in an SiO2 matrix

The kinetics of the decomposition of silicon suboxides (SiO x , 0.7 < x< 1.3) was studied as function of post deposition annealing treatment. Amorphous Si:O:H alloys were deposited by remote plasma enhanced chemical vapor deposition and subjected to rapid thermal anneal. Extent of reaction was monitored by Fourier transform infrared analysis. For all compositions, it was found that there was a fast initial reaction associated with hydrogen loss, followed by a decelatory reaction that is described as 3-dimensional diffusion limited. However the reaction is strongly deceleratory at temperatures less than 900°C, thus SiO x stability is found through kinetic hindrance. Photoluminescence (PL) experiments showed that the decomposition reaction proceeds in the amorphous state with the observation of a-Si PL after high temperature anneals up to 800°C and H 2 plasma passivation.

THERMOCHEMICAL STABILITY OF SILICON-OXYGEN-CARBON ALLOY THIN FILMS : A MODEL SYSTEM FOR CHEMICAL AND STRUCTURAL RELAXATION AT SIC-SIO2 INTERFACES

Alloy thin films of hydrogenated silicon–oxygen–carbon (Si,C)Ox x<2, were deposited and analyzed in terms of changes in structure and bonding as a function of rapid thermal annealing between 600 and 1100 °C using a combination of Fourier transform infrared spectroscopy, Raman scattering and high-resolution transmission electron microscopy. Results showed that three structural/chemical transformations took place upon annealing. The initial reaction (600–800 °C) involved the loss of hydrogen bonded to both silicon and carbon. At intermediate temperatures (900–1000 °C) a Si–O–C type bond was observed to form, and subsequently disappear after annealing to 1050 °C. The formation of ordered amorphous-SiC regions, nanocrystalline-Si regions, and stoichiometric, thermally relaxed SiO2 accompanied the disappearance of the Si–O–C bond at the 1050 °C annealing temperature. Using this alloy as a model system, important information is obtained for optimized processing of SiC–SiO2 interfaces for device applications.

Minimization of sub-oxide transition regions at SiSiO2 interfaces by 900°C rapid thermal annealing

Abstract Combining previously reported optical second harmonic generation (SHG) data with i) newly-reported X-ray photoelectron spectroscopy (XPS) data and ii) the Auger electron spectroscopy (AES) results presented in this paper demonstrates that interfacial sub-oxide bonding (SiOx, x

Interfacial sub-oxide regions at SiSiO2 interfaces: minimization by post-oxidation rapid thermal anneal

Transition regions at Si-SiO 2 interfaces contain suboxide bonding arrangements which contribute to interface roughness and may give rise to electronically active defects. Interfacial transition regions with suboxide bonding are a direct result of thermal and plasma-assisted oxidation at temperatures up to at least 800°C, but sub-oxide bonding is significantly reduced following a 30 s, 900°C RTA. The kinetics of annealing are essentially the same as those for separation of homogeneous sub-oxide thin films (SiO X , x < 2) into silicon nanocrystals and stoichiometric SiO 2 .

A Study of Silicon Suboxide Thin Films by Photoluminescence

Note: IMT-NE Number: 290 Reference PV-LAB-CONF-1998-009 Record created on 2009-02-10, modified on 2017-05-10

New approach to preparing smooth Si(100) surfaces: Characterization by spectroellipsometry and validation of Si/SiO2 interfaces properties in metal‐oxide‐semiconductor devices

Wet chemical removal of thermally grown SiO2 layers on Si(100) substrates has been studied as a function of the pH of the etching solutions in the range of −0.32–1.6 by adding controlled amounts of H2SO4 to a 1:30 HF:H2O mixture. Characterization of the stripped Si(100) surfaces by spectroellipsometry showed that the smoothest surfaces were obtained at a 1:0.50:30 HF (49 wt %):H2SO4(98 wt %):H2O etch with a pH of approximately 0.5. Electrical characterization of metal‐oxide‐semiconductor (MOS) capacitors fabricated on these surfaces with oxide layers prepared by remote plasma enhanced chemical vapor deposition showed (i) the lowest density of interface traps, Dit, (ii) the lowest tunneling currents, J0, and that (iii) the highest breakdown fields, EBD, occurred at the same pH value that produced the smoothest surfaces. In contrast, MOS capacitors fabricated with high‐temperature thermally grown oxides were not significantly affected.

Low pH Chemical Etch Route for Smooth H-Terminated Si(100) And Study Of Subsequent Chemical Stability

To form atomically flat H-passivated Si(100) surfaces, wet chemical etching of sacrificial SiO 2 layer has been examined. Roughness and chemical overlayer thickness, as monitored by ellipsometry shows a minima at an optimal solution of 1:0.5:30 HF(49wt\%):H 2 SO 4 (98wt\%):H 2 O. A mechanistic study offers no evidence for a chemical smoothing from preferential non-Si(100) facet etching. Silicon planarization can be induced by rapid thermal annealing RTA of chemical oxides. The H-terminated Si(100) surfaces are found to be moderately reactive to ambient conditions as monitored by in-situ ellipsometry and Auger analysis. Atomic force microscopy (AFM) measurements show Si(100) surfaces to have a rms ∼1.0A and R max values of 1.6–0.9A. With measured roughness incorporate into ellipsometric model, a 5A native oxide overlayer is rapidly incorporated into the Si(100) surface.