In situ infrared ellipsometry study of the hydrogen incorporation in p-doped amorphous silicon and p-i interfaces

1993 ◽  
Vol 164-166 ◽  
pp. 107-110 ◽  
Author(s):  
R. Ossikovski ◽  
B. Drévillon ◽  
J. Perrin
1992 ◽  
Vol 284 ◽  
Author(s):  
H. Shirai ◽  
B. Drévillon ◽  
R. Ossikovski

ABSTRACTA detailed in situ study, by Infrared Phase Modulated Ellipsometry (IRPME), of interfaces between amorphous silicon (a-Si:H) and silicon nitride (a-SiNx) is presented. A behaviour compatible with a sharp interface is observed when a-SiNx is deposited on top of a-Si:H, the underlayer material being very weakly influenced by the deposition of the overlayer. In contrast a graded transition is observed when a-SiNx is deposited first. In the latter case, the IR measurements directly reveal a nitrogen incorporation in the first monolayers of a-Si:H together with an increase of intensity of the SiH bonds at the interface.


1992 ◽  
Vol 258 ◽  
Author(s):  
B. Drevillon

ABSTRACTRecent applications of spectroscopie phase modulated ellipsometry, from 0.25 to 11 μm, to study the growth of plasma deposited thin film semiconductors like amorphous (a-Si:H) silicon are reviewed. The high sensitivity of this technique is emphasized. In the infrared (IR), the hydrogen incorporation during a-Si:H growth can be precisely investigated. Photoelectronic quality a-Si:H films grow beneath a hydrogen rich overlayer (a few monolayers thick) containing SiH2. the hydrogen being bonded as SiH in the bulk material. In the ultraviolet (UV) range, the ability of kinetic ellipsometry, with fast time resolution, to study interfaces formation is illustrated. Examples of sharp interfaces are presented. In the case of amorphous silicon-silicon nitride structures, it is shown that an inversion of the deposition sequence of the various layers can lead to a graded transition. A detailed analysis of a growth process involving a chemical reaction with the substrate is illustrated in the case the a-Si:H / Pd interface.


1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.


2006 ◽  
Vol 326-328 ◽  
pp. 689-692
Author(s):  
Seung Jae Moon

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during the laser annealing process to fabricate the thin film transistors with uniform characteristics which are used as switches in the active matrix liquid crystal displays. Since it is well known that the physical properties are dependent on the process parameters of the thin film deposition process, the thermal conductivity should be measured. The temperature dependence of the film complex refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the thin film. In-situ transmission signal is obtained during the heating process. The acquired transmission signal is fitted with predictions obtained by coupling conductive heat transfer with multi-layer thin film optics in the optical transmission measurement.


1989 ◽  
Vol 157 ◽  
Author(s):  
Young-Jin Jeon ◽  
M.F. Becker ◽  
R.M. Walser

ABSTRACTThis work was concerned with comparing the relative effects of boron and phosphorus impurities on the solid phase epitaxial (SPE) regrowth rate of self-ion amorphized layers in silicon wafers with (100) orientation. We used previously reported data measured by in situ, high precision, cw laser interferometry during isothermal annealing for temperatures from 450°C to 590°C, and concentrations in the range from 7.8×1018 cm-3 to 5×l020 cm-3 for boron (NB), and from 5×l017 cm-3 to 3×1020 cm-3 for phosphorus (Np) impurities. The basis for the comparison was a recently developed model that extends the Spaepen-Turnbull model for silicon recrystallization to include ionization enhanced processes.The experimental data for bom boron and phosphorus exhibited the linear variation in regrowth rate expected for low concentrations of implanted hydrogenic impurities having a concentration-independent fractional ionization in amorphous silicon. In the linear range the relative enhanced regrowth rate produced by these impurities can be expressed as a product of their, relative fractional ionizations, and the relative amount the rate constant for reconstruction is altered by localizing an electron, or a hole, at the reconstruction site. Assuming that a localized hole and electron equally softened the potential barrier for reconstruction, the experimental results indicated that boron had an ?40 meV lower barrier to ionization in amorphous silicon than phosphorus.The variations in the SPE regrowth rates with higher concentrations of both implanted boron and phosphorus were well fit by quadratic equations, but with different curvatures (+ and - for B and P respectively). This result was interpreted to indicate that SPE regrowth was further enhanced by localized hole pairs, but retarded by localized electron pairs.


1998 ◽  
Vol 538 ◽  
Author(s):  
J. F. Justo ◽  
F. De Brito Mota ◽  
A. Fazziom

AbstractWe combined empirical and ab initio methods to study structural and electronic properties of amorphous silicon nitride. For such study, we developed an interatomic potential to describe the interactions between silicon, nitrogen, and hydrogen atoms. Using this potential, we performed Monte Carlo simulations in a simulated annealing scheme to study structural properties of amorphous silicon nitride. Then this potential was used to generate relevant structures of a-SiNx:Hy which were input configurations to ab initio calculations. We investigated the electronic and structural role played by hydrogen incorporation in amorphous silicon nitride.


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