Process Control of LED Thin Films Through Optical Metrology
Source: LED Japan Conference, Strategies in Light 2012
Author: Padraig Murphy
Abstract: High-speed, high resolution, non-destructive measurements of thickness, n and k
spectra from 190nm – 1000nm, and energy band gap (Eg) of LED thin films are presented. The
measurements are based on utilization of n&k Technology’s n&k Gemini, a thin film optical me-
trology system that simultaneously provides reflectance (R) and transmittance (T) raw data, from
190nm – 1000nm with a 50 mm spot for both R and T. Results for GaN/Sapphire-Substrate,
In1-xGaxN/GaN/Various Underlayers/Sapphire-Substrate, Polyimide/Glass-Substrate, and Alq3/
Glass-Substrate are shown. In addition, from inspection of the n and k spectra of In1-xGaxN it is
demonstrated that the concentration of In in In1-xGaxN can be determined.
Measurement of Thin Films Inside Encapsulated OLED/PLEDs.
Source: n&k Technology Application Bulletin (#19), January 2004
Author: n&k Technology Applications Group
Abstract: The light-emitting polymer technology for flexible organic/polymer light emitting diode
(OLED/PLED) information displays is a fast-growing market. n&k Analyzers are currently being
used for monitoring thickness and optical properties of ITO anode layer, polymer buffer layer and
polymer light emitting layer inside the encapsulated OLED/PLED device.
Measurement of LCOS Display Cell Gap.
Source: n&k Technology Application Bulletin (#15), October 2002.
Author: n&k Technology Applications Group
Abstract: n&k Analyzers are currently being used to monitor several parameters within the LCOS
display during manufacturing. In addition to these film measurements, the n&k Analyzer has the
capability to accurately measure and map, the cell (or air) gap provided for the liquid crystal. The
thickness and uniformity of the cell gap is critical to display performance.
Cross-Linking Thin Film Characterization Technique for Data Storage, Semiconductor, and
Flat Panel Display Devices
Source: SPIE Photonic (1999)
Authors: I. Bloomer, D. Harrison (n&k); S. Prakash (DAS); K. Zhang (EG&G); S. Lian (Motorola)
Abstract: The message of this paper is that the n&k Analyzer is a universal thin film characteriza-
tion tool. The applicability of the n&k Analyzer various films used in different industries are de-
scribed in this article by Dr. Shiva Prakash of DAS Devices, Dr. Sean Lian of Motorola, and Dr.
Zhang of EG&G.
Patternability, and Manufacturability of ITO Films
Source: SPIE (1998)
Authors: D. Bloom, G.G. Li, K. Zhang, A.R. Forouhi, I. Bloomer
Abstract: ITO is a transparent conductor, used for flat panel display applications. Therefore its
thickness, transparency, and conductivity must be measured and controlled. Dr. Zhang of EG&G
worked with us to characterize ITO films processed under various deposition conditions.
The n&k Analyzer was able to determine the thickness, n and k spectra, reflectance (R), and
transmittance (T) of the films. Furthermore, the k spectra of the ITO film was correlated to its
resistivity. This is an important correlation because it opens the door to a non-contact determina-
tion of resistivity. The standard method relies on the four-point probe that involves touching the
film and furthermore can be operator-sensitive.
Thus, it was demonstrated that n&k Analyzer can be used for complete characterization of ITO.
Effect of Process Parameters on the Amorphous and the Crystalline Structure of Sn-
doped Indium Oxide Films
Source: Optical Interface Coatings Topical Meeting (1998)
Author: B. Heinz (Leybold Materials)
Abstract: DC magnetron sputtering is the dominant deposition process for the high volume
production of ITO (Indium-Tin-Oxide) thin films. Most of the applications require low resistivity
and highly transparent layers. Depending on the process conditions the deposited ITO is either
amorphous or crystalline. The major parameters, which influence the structure and the film per-
formance, will be discussed. The emphasis is on conditions, which allow optimizing the optical
as well as the electronic performance.
In this paper, authored by Bernd Heinz of Leybold Materials, Inc., an n&k Analyzer Model 1280
was used to characterize the optical properties of films deposited under differing conditions.
Studies of RF Sputtered CrSiOx and SiC as Series Resistor Films in FED Displays
Authors: R.S. Nowicki, B. Pogemiller, J.E. Pogemiller (Coloray); A.R. Forouhi, I. Bloomer (n&k);
W.M Clift, J.L. Yio, T. Felter (Sandia Nat’l Labs)
Abstract: In this paper, authored by Ronald Nowicki, Heinze Busta, and Jay Pogemiller of Col-
oray Display Corp.; Dr. Rahim Forouhi, and Dr. Iris Bloomer of n&k Technology; and W. Miles
Clift, Ja Lee Yio and Tom Felter of Sandia National Labs, an n&k Analyzer was used to measure
the optical properties of the various as-deposited and heat-treated films.
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