X-ray or gamma ray systems or devices – Specific application – Fluorescence
Reexamination Certificate
2002-12-04
2004-12-07
Glick, Edward J. (Department: 2882)
X-ray or gamma ray systems or devices
Specific application
Fluorescence
C378S045000, C378S050000, C438S014000, C438S486000
Reexamination Certificate
active
06829328
ABSTRACT:
This application claims the benefit of the Korean Application No. P2001-88450 filed in Korea on Dec. 29, 2001, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for making a quantitative analysis of nickel, and more particularly, to a method for making a quantitative analysis of nickel to determine an amount of nickel required for converting amorphous silicon into polycrystalline silicon by MIC (Metal Induced Crystallization).
2. Description of the Related Art
Due to features of the Liquid Crystal Display (LCD), such as a low driving voltage, a low power consumption, full-color realization, light weight, compactness, and the like, application of the LCD varies widely. For example, devices, such as watches, calculators, monitors for PCs, and notebook computers, TVs, instrument panel for an airplane, PDA (Personal Digital Assistants) and mobile stations use an LCD. Typically, an LCD includes a liquid crystal display panel part for displaying a picture, and a circuit part for driving the liquid crystal display panel. The liquid crystal display panel part has a first substrate having thin film transistor (TFT) array formed thereon, a second substrate having color filter array formed thereon, and a liquid crystal layer formed between the two substrates.
The first substrate of the LCD, having the TFT array formed thereon, has a plurality of gatelines arranged in one direction at fixed intervals and a plurality of datalines arranged in a direction perpendicular to the gatelines at fixed intervals. Pixel regions are defined between the gatelines and the datalines. A pixel electrode is formed in each pixel region. A plurality of thin film transistors are formed in the pixel regions adjacent to where the gatelines and the datalines cross, respectively. The gate, source and drain of each thin film transistor are respectively connected to a gateline, dataline and a pixel electrode. Each thin film transistor is turned on/off in response to a driving signal from the gateline such that a picture signal is transmitted from the dataline to the pixel electrode.
The second substrate of the LCD, having the color filter array formed thereon, has a black matrix layer for shielding light from parts of the pixel regions. A RGB color filter layer is formed opposite to the pixel regions for displaying colors. A common electrode is formed on the entire surface of the second substrate, including the color filter layer. In an alternative, the common electrode may be formed on the first substrate in an In Plane Switching (IPS) mode LCD.
The foregoing first and second substrates are bonded together such that a gap is maintained between the two substrates. In the alternative, spacers can be positioned between the substrates to assist in maintaining a uniform gap across the LCD. A liquid crystal layer is positioned in the gap between the two substrates.
In order for an LCD to have high definition and high resolution, especially for moving images, a high speed or highly responsive thin film transistor is required. A high speed thin film transistor requires a high degree of electrophoresis in the active layer of the thin film transistor. Thus, a polycrystalline silicon layer, rather than an amorphous layer, is used to increased the degree of electrophoresis in the active layer. Further, the use of the polycrystalline silicon as an active layer enables cost reduction of a driving Integrated Circuit (IC) by forming the driving IC on the first substrate having the TFT array formed thereon, which facilitates easy fitting since the driving IC is not on a separate substrate. Furthermore, using polycrystalline silicon reduces power consumption since polycrystalline silicon has less resistance than amorphous silicon.
The polycrystalline silicon cannot be deposited directly on the glass substrate of the LCD because of the high temperature for such a polycrystalline deposition. However, amorphous silicon can be deposited on the glass substrate. Then, the amorphous silicon is crystallized into polycrystalline silicon.
The amorphous silicon may be crystallized into polycrystalline silicon by either a solid state crystallizing method or a Continuous Grain Silicon (CGS) method. In the solid state crystallization method, amorphous silicon is deposited on the substrate. The amorphous silicon is then crystallized by using a heat treatment of about 20 hours at 600° C. under a vacuum. In the CGS method, amorphous silicon is deposited on the glass substrate, the part in which a channel region of the thin film transistor is to be formed therein is masked off by a silicon oxide film, or the like. Then a Ni layer is deposited on the amorphous silicon such that Ni is not deposited on the channel part and the thickness of Ni on the source/drain regions of the thin film transistor is greater than a few tens of Å. Subsequently, the amorphous silicon is crystallized into polycrystalline silicon. The source and drain regions crystallize due to the Ni on their surfaces and the channel region crystallizes towards its center from the crystallized source and drain regions. The semiconductive properties of the source and drain regions have been diminished because of the large presence of Ni while the channel region is only slightly effected by trace amounts of Ni that may have migrated from the source and drain regions.
Typically, nickel is used when amorphous silicon is crystallized using a metal. Nickel improves speed and completeness of the crystallization of amorphous silicon into polycrystalline silicon. However, too much nickel undermines the semiconductive properties of the subsequently formed polycrystalline silicon. Accordingly, crystallizing amorphous silicon using a nickel needs a method for accurately measuring and/or determining quantity of nickel deposited on amorphous silicon.
A related art method for making quantitative analysis of nickel will be explained, with reference to the attached drawing.
FIG. 1
explains a related art method for making a quantitative analysis of nickel. Measuring a thickness of deposited nickel is effective in making a quantitative analysis of nickel. Physical properties of a surface and a thickness of a thin film can be detected by using an ellipsometer. As shown in
FIG. 1
, an ellipsometer includes a light source
102
, a polarizing prism
103
for linearly polarizing light from the light source, a quarter wave compensator
104
for elliptically polarizing the linearly polarized light, an analyzer
105
for analyzing a light that is reflected from and refracted at a specimen
101
, and a light detector
106
for detecting the light through the analyzer
105
.
A related art method for measuring a thickness of a thin film by using the ellipsometer will be explained in reference to FIG.
1
. The polarizing prism
103
and the quarter wave compensator
104
are rotated such that light is having elliptically polarized by the polarizing prism
103
and the quarter wave compensator
104
. The elliptically polarized light is incident to a surface of a specimen
101
, reflected, and refracted at the specimen
101
, is linearly polarized.
Eventually, a thickness of the specimen can be measured by an equation which describes optical characteristics of the specimen
101
and is derived from optical parameters by using rotation angles of the polarizing prism
103
, the quarter wave compensator
104
, and the analyzer
105
. The thickness can be measured to a few thousands of Å. Thus, a thickness of nickel sputtered on amorphous silicon can be measured by using the ellipsometer.
However, the foregoing related art method for making a quantitative analysis of nickel by a thickness measurement using an ellipsometer has the following problems. First, measurement of the thickness is complicated since the thickness is measured by using a polarized light incident to a specimen. Second, the analysis costs are high because of the equipment used to measure thickness with polarized light incident to the spec
Kim Binn
Kwon Hyun Ja
Park Kyu Ho
Glick Edward J.
LG. Philips LCD Co. Ltd.
Morgan & Lewis & Bockius, LLP
Thomas Courtney
LandOfFree
Method for making quantitative analysis of nickel does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for making quantitative analysis of nickel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for making quantitative analysis of nickel will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3307684