Combinatorial molecular layer epitaxy device

Details Combinatorial molecular layer epitaxy device Combinatorial molecular layer epitaxy device

2000-05-09

2002-02-05

Kunemund, Robert (Department: 1765)

Single-crystal, oriented-crystal, and epitaxy growth processes;

Apparatus

With means for measuring, testing, or sensing

C117S202000, C117S108000, C117S900000, C118S715000, C118S719000, C118S729000, C118S730000

Reexamination Certificate

active

06344084

ABSTRACT:

TECHNICAL FIELD
This invention relates to a combinatorial molecular layer epitaxy apparatus that is useful to form an inorganic superstructure, a metallic superstructure or an organic superstructure, especially to make an efficient search for substances in a short period of time.
The invention further relates to a combinatorial molecular layer epitaxy apparatus that permits a substrate or substrates to be conveyed in the apparatus as a thin film forming system and, to be conveyed in a state in which they remain heated, and successive processing chambers to be formed as independent vacuum chambers with pressure and temperatures therein controllable independently of one chamber from another.
BACKGROUND ART
At recent times, following the discovery of lanthanum/barium/copper-oxide superconductive materials, a great progress has been made of thin film forming technologies for high temperature superconducting oxides. With such a progress, efforts have been expended extensively to search for and to investigate a variety of new functional substances for metallic, inorganic and organic materials.
In the field of forming thin films of high temperature superconducting oxides, the fact that a functional oxide material such as of perovskite type is itself a multicomponent material with a plurality of oxides makes it difficult to theoretically predict an optimized component proportion and a correlation between thin film preparing conditions and resultant properties, and provides no alternative but to adopt a trial and error approach for optimization.
Under the circumstances, X. -D. Xiang et al conducted a search for oxide high temperature super-conductors on combining a multi-sputtering thin film forming process with a mask patterning technique of covering particular areas on a substrate with masks, and effecting a combinatorial synthesis of inorganic materials in which a number of inorganic substances are synthesized parallel to each other, and showed that this approach had a power in functional search for a multicomponent material (X. -D. Xiang et al, Science, 268, 1738 (1995)).
Also, G. Briceno et al in search for colossal magnetoresistance (CMR) materials, prepared from a new material: LnXMYCoO
3−&dgr;
(Ln=La, Y; M=Ba, Sr, Ca, Pb) with cobalt oxide as its base component, 128 specimens with varied compositions sputter-evaporated using combinatorial synthesis and thereafter sintered in an oxygen atmosphere. And based on the measurement of magnetic resistance of those specimens, they revealed that even a multi-oxide material exhibited a maximum magnetic resistance ratio 72% CMR. Significantly, discovery and optimization of a new CoO
2
-based CMR material were achieved on conducting a combinatorial synthesis only twice with varied sintering conditions.
It can be seen, however, that a combinatorial synthesis referred to above for inorganic materials in which forming thin films are effected at a room temperature in either case only plays a role of simply controlling compositions. Also, no combinatorial synthesis has become a reality of thin films with a superstructure formed by epitaxial growth for each of molecular layers of materials either organic or inorganic.
On the other hand, it is noted that in a conventional thin film manufacturing system which involves a plurality of processing stages, wafers have been conveyed between different process stages by man or a robot, pressure and temperature process parameters have been set up for the individual processing stages one after another.
Especially where a wafer is required to have a clean surface, wafers must be conveyed through a conveying path that is hermetically sealed in a clean space.
Since such a conveyer is normally not adapted for high temperature wafers, however, it has been common to rely on a time consuming procedure in which hot wafers processed in a given process stage is cooled to a room temperature and then conveyed into a next process stage where they are heated to a required temperature for processing.
Further, the need to set up process parameters such as a reaction pressure and a wafer temperature one after another for the successive processing stages individually makes it unsuitable to process wafers continuously in different process stages.
Accordingly, the present invention is provided to resolve such problems met in the prior art as described, and has for its first object to provide a combinatorial molecular layer epitaxy apparatus that permits molecular layers to be formed each individually by epitaxial growth to form an inorganic, metallic or organic superstructure of such molecular layers, and that allows an efficient search for a substance to be conducted in a short period of time.
Another object of the present invention resides in providing a combinatorial molecular layer epitaxy apparatus that is capable of conveying wafers in their heated state, and permits successive processing chambers to be formed as independent vacuum chambers with pressure and temperatures therein controllable independently of one chamber from another.
DISCLOSURE OF THE INVENTION
In order to achieve the first object mentioned above, the present invention provides a combinatorial molecular layer epitaxy apparatus that comprises a common chamber having pressure therein controllable; one or more conveyable substrate heating units having a substrate holder for holding one or more substrates in the common chamber; and one or more process conducting chambers having pressure therein controllable and provided to correspond to the substrate heating units, the said process conducting chambers including a growth chamber which has a multiple raw material supply means for supplying raw materials onto a said substrate held by a said substrate heating unit, a gas supply means for feeding a gas onto a surface of the substrate, and an instantaneous observation means for instantaneously observing epitaxial growth of monomolecular layer for each of the layers on the substrate surface, thereby permitting growth temperature, pressure and supply of the raw materials to be controlled for each of the substrates and producing a group of substances caused each to grow epitaxially in an individual monomolecular layer and brought together in a single series of reactions for each of the substrates, systematically in accordance with indications of the instantaneous observation means.
The construction described above permits [multiple raw materials]×[multiple substrates]×[reaction parameters such as temperature, pressure and flux (rate of build-up) from gas phase] to be selected or controlled independently of one another and put together in any desired combination, and hence is capable of synthesizing or bringing together in a single series of reactions a group of substances into an epitaxial growth superlattice structure systematically controlled.
Also, in a combinatorial molecular layer epitaxial growth apparatus according to the present invention, the multiple raw material supply means preferably includes a laser molecular beam epitaxy means for vaporizing with an excimer laser beam a plurality of targets of different solid raw materials and for forming a thin film of a composition as aimed on each of the substrates.
This construction permits a limited depth of surface of a target to be momentarily vaporized and gasified and a thin film of a composition as aimed to be formed. It is possible to form a thin film, e. g., of an inorganic superstructure.
Also, in a combinatorial molecular layer epitaxial growth apparatus according to the present invention, the multiple raw material supply means may preferably include a laser molecular beam epitaxy means and a said substrates is composed of a material selected from the group which consists of &agr;-Al
2
O
3
, YSZ, MgO, SrTiO
3
, LaAlO
3
, NdGaO
3
, YAlO
3
, LaSrGaO
4
, NdAlO
3
, Y
2
O
5
, SrLaAlO
4
, CaNdAlO
4
, Si and compound semiconductors. Further, the target solid raw materials may include substances adapted to form a material selected from the group which

Affiliated with

Also associated with

Rating

Combinatorial molecular layer epitaxy device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Combinatorial molecular layer epitaxy device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Combinatorial molecular layer epitaxy device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2980164