Real-time Monitoring of semiconductor growth by Spectroscopic ellipsometry

1997 ◽  
Vol 502 ◽  
Author(s):  
B. Johs ◽  
J. Hale ◽  
C. Herzinger ◽  
D. Doctor ◽  
K. Elliott ◽  
...  
Keyword(s):  
Data Analysis ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Growth Parameters ◽  
High Surface ◽  
Buffer Layers ◽  
Ex Situ ◽  
Angle Of Incidence ◽  
Time Layer ◽  
Analysis Strategies

ABSTRACTin situ Spectroscopic Ellipsometry (SE) is an optical technique which is well suited for the monitoring of epitaxial semiconductor growth, due to its high surface sensitivity and non-invasive nature. In this work, SE systems were installed on both MBE and MOCVD deposition systems to monitor the epitaxial growth of InxGa1−xAs and InxAl1−xAs compounds on InP substrates. The structures grown include thick lattice matched In0.53Ga0.47As buffer layers (for HBT collectors), and strained RTD structures. SE was used to monitor in real-time layer composition and thickness during growth. To enhance the precision and accuracy of the SE determined growth parameters, it was necessary to optimize the SE data analysis strategies. A methodology to determine the best spectral region for the SE data analysis in the presence of noise and systematic effects (such as angle of incidence uncertainty, detector wavelength shifts, surface roughness, uncertainty in surface temperature, non-ideal growth modes, etc.) is presented. Using the optimized data analysis strategies, long term SE-determined InxGa1−�As composition accuracy (as verified by ex situ x-ray measurements) of ±0.002 in ‘x’ was achieved. SE thickness measurements of ultra-thin (<30Å) strained AlAs barrier layers were also in excellent agreement (±0.5Å) with real-time photo-emission oscillation measurements.

Optical and Physical Characterization of Cu2-xSe Thin Films for Real Time Spectroscopic Ellipsometry on Cu(In,Ga)Se2-based Photovoltaic Devices

2009 ◽  
Vol 1210 ◽  
Author(s):  
James D Walker ◽  
Himal Khatri ◽  
Scott Little ◽  
Vikash Ranjan ◽  
Robert Collins ◽  
...  
Keyword(s):  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Growth Temperature ◽  
Room Temperature ◽  
Optical Model ◽  
High Efficiency ◽  
Optical Feedback ◽  
High Surface ◽  
Ex Situ ◽  
Photovoltaic Devices

AbstractIn situ, real time spectroscopic ellipsometry (RTSE) has been used to study the growth processes and optical properties of Cu2-xSe - an important binary compound in the fabrication of high efficiency copper indium gallium diselenide (CIGS) photovoltaic devices. It was found that the high surface roughness of the Cu2-xSe layers necessitated a “graded” optical model in order to extract meaningful dielectric functions at both 550 °C and room temperature. The optical model was verified at room temperature against SEM micrographs and reflectance measurements carried out ex situ. The growth temperature dielectric functions presented in this study are expected to allow for a greater level of control and understanding of the so-called 2- and 3-stage processes for CIGS fabrication in which a Cu2-xSe phase, present at the CIGS grain boundaries, acts as a fluxing agent for the growth of photovoltaic quality CIGS. Real time optical feedback via RTSE combined with the growth temperature dielectric functions presented here could play an important role in improving material fabrication on both the laboratory and industrial scales.

Real-Time Analysis Of In-Situ Spectroscopic Ellipsometric Data During Mbe Growth Of III-V Semiconductors

1991 ◽  
Vol 222 ◽  
Author(s):  
B. Johs ◽  
J. L. Edwards ◽  
K. T. Shiralagi ◽  
R. Droopad ◽  
K. Y. Choi ◽  
...  
Keyword(s):  
Real Time ◽  
Optical Constants ◽  
Growth Parameters ◽  
Ex Situ ◽  
Time Analysis ◽  
Mbe Growth ◽  
In Situ Data ◽  
Real Time Analysis

ABSTRACTA modular spectroscopic ellipsometer, capable of both in-situ and ex-situ operation, has been used to measure important growth parameters of GaAs/AIGaAs structures. The ex-situ measurements provided layer thicknesses and compositions of the grown structures. In-situ ellipsometric measurements allowed the determination of growth rates, layer thicknesses, and high temperature optical constants. By performing a regression analysis of the in-situ data in real-time, the thickness and composition of an AIGaAs layer were extracted during the MBE growth of the structure.

Real-Time Diagnosis of Etching and Deposition Processes by Spectroscopic Ellipsometry

1983 ◽  
Vol 29 ◽  
Author(s):  
D. E. Aspnes ◽  
R. P. H. Chang
Keyword(s):  
High Pressure ◽  
Data Analysis ◽  
Laser Beam ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Chemical Etching ◽  
Polarization State ◽  
Surface Information ◽  
Deposition Processes ◽  
Time Diagnosis

ABSTRACTRecent advances in instrumentation and data analysis have made spectroscopic ellipsometry a routine analytic tool with submonolayer sensitivity for monitoring and controlling cleaning, etching, deposition, or other processes that take place in relatively high-pressure or reactive environments. We discuss representative applications in chemical etching, plasma processing, and MOCVD to illustrate analytical procedures and to indicate other potential uses of the technique. The possibility of extracting surface information already carried in the polarization state of the processing laser beam is also discussed.

Real-Time Spectroscopic Ellipsometry of Sputtered CdTe Thin Films: Effect of Ar Pressure on Structural Evolution and Photovoltaic Performance

2009 ◽  
Vol 1165 ◽  
Author(s):  
Michelle Nicole Sestak ◽  
Jian Li ◽  
Naba Raj Paudel ◽  
Kristopher Wieland ◽  
Jie Chen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Volume Fraction ◽  
Photovoltaic Performance ◽  
Structural Evolution ◽  
Ex Situ ◽  
Force Microscopy ◽  
Bulk Layer ◽  
Cdte Films

AbstractIn this study, 1 μm thick polycrystalline CdTe films were deposited by magnetron sputtering using a variable argon pressure, 2.5 ≤ pAr ≤ 50 mTorr, and a fixed substrate temperature, Ts = 230°C. Real time spectroscopic ellipsometry (RTSE) was performed during deposition in order to analyze the nucleation and coalescence, as well as the evolution of the surface roughness thickness ds with bulk layer thickness db and the depth profile in the void volume fraction fv. A linear correlation was found between the final ds value measured by RTSE at the end of deposition and the root-mean-square (rms) surface roughness measured by atomic force microscopy (AFM) ex situ after deposition. A monotonic decrease in RTSE-determined roughness thickness is observed with decreasing Ar pressure from 18 to 2.5 mTorr. The lowest pressure also leads to the greatest bulk layer structural uniformity; in this case, fv increases to 0.04 with increasing CdTe thickness to 1 μm. The photovoltaic performance of CdTe films prepared with the lowest pressure of pAr = 2.5 mTorr is compared with that of previously optimized CdTe solar cells with pAr = 10 mTorr.

scholarly journals Towards Real-Time In-Situ Mid-Infrared Spectroscopic Ellipsometry in Polymer Processing

2021 ◽  
Author(s):  
Alexander Ebner ◽  
Robert Zimmerleiter ◽  
Kurt Hingerl ◽  
Markus Brandstetter
Keyword(s):  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Quantum Cascade Lasers ◽  
Polymer Processing ◽  
In Situ Monitoring ◽  
Acquisition Time ◽  
Angle Of Incidence ◽  
Mid Infrared ◽  
Ethylene Vinyl Alcohol

Recent developments in mid-infrared (MIR) spectroscopic ellipsometry enabled by quantum cascade lasers (QCLs) resulted in a drastic improvement in signal-to-noise ratio compared to conventional thermal emitter based instrumentation. Thus, it was possible to reduce the acquisition time for high-resolution broadband ellipsometric spectra from multiple hours to less than 1 second. This opens up new possibilities for real-time in-situ ellipsometry in polymer processing. To highlight these evolving capabilities we demonstrate the benefits of a QCL based MIR ellipsometer by investigating single and multilayered polymer films. The molecular structure and reorientation of a 2.5m thin biaxially oriented polyethylene terephtalate film is monitored during a stretching process lasting 24.5 s to illustrate the perspective of ellipsometric measurements in dynamic processes. In addition, a polyethylene/ethylene vinyl alcohol/polyethylene multilayer film is investigated at continuously varying angle of incidence ( 0∘ &ndash; 50∘) in 17.2 s, highlighting an unprecedented sample throughput for the technique of varying angle spectroscopic ellipsometry in the MIR spectral range. The obtained results underline the superior spectral and temporal resolution of QCL ellipsometry and qualify this technique as suitable method for advanced in-situ monitoring in polymer processing.

scholarly journals Real time and ex situ spectroscopic ellipsometry analysis microcrystalline silicon thin films growth

2012 ◽  
Vol 61 (3) ◽  
pp. 036802
Author(s):  
Li Xin-Li ◽  
Gu Jin-Hua ◽  
Gao Hai-Bo ◽  
Chen Yong-Sheng ◽  
Gao Xiao-Yong ◽  
...  
Keyword(s):  
Thin Films ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Ex Situ ◽  
Microcrystalline Silicon ◽  
Silicon Thin Films

scholarly journals Towards Real-Time In-Situ Mid-Infrared Spectroscopic Ellipsometry in Polymer Processing

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 7
Author(s):  
Alexander Ebner ◽  
Robert Zimmerleiter ◽  
Kurt Hingerl ◽  
Markus Brandstetter
Keyword(s):  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Quantum Cascade Lasers ◽  
Polymer Processing ◽  
In Situ Monitoring ◽  
Acquisition Time ◽  
Angle Of Incidence ◽  
Mid Infrared ◽  
Ethylene Vinyl Alcohol

Recent developments in mid-infrared (MIR) spectroscopic ellipsometry enabled by quantum cascade lasers (QCLs) have resulted in a drastic improvement in signal-to-noise ratio compared to conventional thermal emitter based instrumentation. Thus, it was possible to reduce the acquisition time for high-resolution broadband ellipsometric spectra from multiple hours to less than 1 s. This opens up new possibilities for real-time in-situ ellipsometry in polymer processing. To highlight these evolving capabilities, we demonstrate the benefits of a QCL based MIR ellipsometer by investigating single and multilayered polymer films. The molecular structure and reorientation of a 2.5 µm thin biaxially oriented polyethylene terephthalate film is monitored during a stretching process lasting 24.5 s to illustrate the perspective of ellipsometric measurements in dynamic processes. In addition, a polyethylene/ethylene vinyl alcohol/polyethylene multilayer film is investigated at a continuously varying angle of incidence (0∘– 50∘) in 17.2 s, highlighting an unprecedented sample throughput for the technique of varying angle spectroscopic ellipsometry in the MIR spectral range. The obtained results underline the superior spectral and temporal resolution of QCL ellipsometry and qualify this technique as a suitable method for advanced in-situ monitoring in polymer processing.

Mapping the Phase-Change Parameter Space of Hot-Wire CVD Si:H Films Using In-Situ Real Time Spectroscopic Ellipsometry

2002 ◽  
Vol 715 ◽  
Author(s):  
Dean H. Levi ◽  
Brent P. Nelson ◽  
John D. Perkins
Keyword(s):  
Surface Roughness ◽  
Real Time ◽  
Parameter Space ◽  
Spectroscopic Ellipsometry ◽  
Film Growth ◽  
Growth Parameter ◽  
Ex Situ ◽  
Degree Of Crystallinity ◽  
Hot Wire

AbstractIn-situ real-time spectroscopic ellipsometry (RTSE) provides detailed information on the evolution of the structural and optical properties of Si:H films during film growth. We have used in-situ RTSE to characterize the film morphology and crystallinity of hot-wire CVD (HWCVD) Si:H films as a function of hydrogen dilution R=[H]/[H+SiH4], substrate temperature Ts, and film thickness db. Transitions from one mode of film growth to another are indicated by abrupt changes in the magnitude of the surface roughness during film growth. The degree of crystallinity of the film can be determined from the bulk dielectric function. We have studied the growth parameter space consisting of R from 0 to 12, Ts from 150°C to 550°C, and db from 0 to 1 um. For each set of R and Ts values, the structural evolution of the film can be characterized by the shape of the surface roughness thickness ds versus bulk thickness db curve. In contrast to studies done by Collins et al on PECVD growth of Si:H films, our studies of HWCVD growth find no conditions where ds remains constant after coalescence of the initial nucleation centers. Most of the films grown within the range of parameters studied exhibit a secondary nucleation and coalescence signature. The transition between a-Si:H and uc-Si:H growth is near the R=3 to R=4 dividing line. Initial coalescence of purely uc-Si:H material doesn't occur until R>8. We have verified the RTsE crystallinity classification using ex-situ Raman scattering.

In Situ Spectroscopic Ellipsometry for Real Time Semiconductor Growth Monitor

1990 ◽  
Vol 216 ◽  
Author(s):  
Blaine Johs ◽  
Duane Meyer ◽  
Gerald Cooney ◽  
Huade Yao ◽  
Paul G. Snyder ◽  
...  
Keyword(s):  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Ex Situ ◽  
Mbe Growth ◽  
Materials Analysis ◽  
Spectroscopic Ellipsometer

ABSTRACTA modular spectroscopic ellipsometer for in situ and ex situ materials analysis is described, and results for in situ MBE growth of GaAs/AlGaAs are reported.

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