Porosity depth profiling of thin porous silicon layers by use of variable-angle spectroscopic ellipsometry: a porosity graded-layer model

1998 ◽  
Vol 37 (19) ◽  
pp. 4130 ◽  
Author(s):  
Leif A. A. Pettersson ◽  
Lars Hultman ◽  
Hans Arwin
Keyword(s):  
Porous Silicon ◽  
Spectroscopic Ellipsometry ◽  
Depth Profiling ◽  
Layer Model ◽  
Variable Angle ◽  
Variable Angle Spectroscopic Ellipsometry

Microstructural Analysis and Modelling of Thin Porous Silicon Layers with Variable Angle Spectroscopic Ellipsometry

1996 ◽  
Vol 431 ◽  
Author(s):  
L. A. A. Pettersson ◽  
S. Zangooie ◽  
R. Bjorklund ◽  
H. ARWIN
Keyword(s):  
Porous Silicon ◽  
Amorphous Silicon ◽  
Spectral Range ◽  
Spectroscopic Ellipsometry ◽  
Crystalline Silicon ◽  
Microstructural Analysis ◽  
Weighted Average ◽  
Constant Current ◽  
Variable Angle ◽  
Variable Angle Spectroscopic Ellipsometry

AbstractThin porous silicon (PS) layers (30–1000 nm) have been produced by electrochemical anodization of highly p-doped silicon in a hydrofluoric acid electrolyte at constant current density. Variable angle spectroscopic ellipsometry was used for characterization in the spectral range 1.24–5.00 eV. Four multilayer models were developed for the PS layers. Ellipsometric spectra were fitted for three of these models by utilizing an effective medium approximation for each sublayer containing crystalline silicon and voids. A third constituent, amorphous silicon, was added in the fourth model. Excellent fits to experimental data were obtained in the entire spectral range and thickness and composition of each individual sublayer in the models were determined. The analyses revealed a compositional gradient normal to the surface. The porosity and the fraction of amorphous silicon decreased with film depth, whereas the fraction of crystalline silicon increased. The mean porosity of a PS layer was obtained as the thickness weighted average of the porosities of the sublayers. The proposed multilayer models allow a more detailed analysis of PS layers compared to single layer models.

scholarly journals Thin‐film hermeticity: A quantitative analysis of diamondlike carbon using variable angle spectroscopic ellipsometry

1988 ◽  
Vol 64 (8) ◽  
pp. 4175-4180 ◽  
Author(s):  
S. Orzeszko ◽  
Bhola N. De ◽  
John A. Woollam ◽  
John J. Pouch ◽  
Samuel A. Alterovitz ◽  
...  
Keyword(s):  
Thin Film ◽  
Quantitative Analysis ◽  
Spectroscopic Ellipsometry ◽  
Variable Angle ◽  
Diamondlike Carbon ◽  
Variable Angle Spectroscopic Ellipsometry

In-line Characterization of Thin Polysilicon Films by Variable Angle Spectroscopic Ellipsometry

2000 ◽  
Vol 609 ◽  
Author(s):  
S. Paprotta ◽  
K. S. Röver ◽  
R. Ferretti ◽  
U. Höhne ◽  
J. D. Kähler ◽  
...  
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Complex Refractive Index ◽  
Deposition Process ◽  
Oxide Thickness ◽  
Interface Layer ◽  
Parameter Determination ◽  
Variable Angle ◽  
Air Interface ◽  
Polysilicon Films ◽  
Variable Angle Spectroscopic Ellipsometry

ABSTRACTUp to now an in-line method for parameter determination of deposited thin polysilicon films is not available. In this paper a method for monitoring the polysilicon deposition process in device manufacturing by variable angle spectroscopic ellipsometry (VASE) is demonstrated. Therefore several polysilicon films are deposited on thermally oxidized [100] silicon wafers. These samples are characterized by VASE in the optical range of 450 - 850 nm. Parameters are determined by simulation using a multilayer model consisting of air, interface layer (surface roughness), polysilicon, SiO2 and silicon substrate. Different optical models representing the properties of polysilicon are tested. The free parameters are the oxide thickness, the composition and the thickness of the interface layer (air, polysilicon) as well as the thickness and the complex refractive index of the polysilicon layer. Results of the spectroscopic analysis are verified by AFM and SEM measurements. It can be shown that parameters of the deposited polysilicon films, which often could only be determined by complex and destructive off-line analysis methods are also accessible by non-destructive in-line VASE measurements.

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