Stable hydride source compositions for manufacture of...

Details Stable hydride source compositions for manufacture of... Stable hydride source compositions for manufacture of...

2000-06-26

2001-11-20

Langel, Wayne (Department: 1754)

Coating processes

Direct application of electrical, magnetic, wave, or...

Ion plating or implantation

C427S250000, C427S252000, C427S576000, C427S585000, C427S586000

Reexamination Certificate

active

06319565

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the stabilization of hydrides and other compositions in which deuterium and/or tritium may be substituted to derivatize the hydride composition and produce a highly stabilized deutero- and/or tritiato-species. In a particular aspect, the invention relates to reagents useful as metal source compositions for ion implantation, chemical vapor deposition, laser or light-induced deposition, plasma-induced or ion beam-induced deposition, or other metal formation processes, in which the metal source compositions have been stabilized by the incorporation of deuterium and/or tritium substituents therein.
2. Description of the Related Art
In the fabrication of advanced semiconductor devices, processes such as III-V MOCVD and p
doping by ion implantation ideally require the use of Group III and Group V hydrides.
However, the hydrides of the heavier elements of Group III and Group V are unstable or in some cases are simply not known. For instance, stibine is only stable at very low temperatures (−78° C.), decomposing spontaneously at room temperature, while indane cannot be isolated.
In addition, alkyl or aryl metal hydrides such as HSbR
2
and H
2
SbR, wherein R is alkyl, are also unstable.
Although literature reports indicate that researchers have synthesized and used metal hydrides as precursors when stored at low temperatures, widespread commercialization has not been possible due to the limited stability of the hydrides to light, heat and metal surfaces (i.e., stainless steel).
Sophisticated microelectronic components and device heterostructures are driving the development of CVD precursors that exhibit useful volatility and the ability to deposit high-purity films. Currently, many III-V devices based upon strained layer superlattices and multiple quantum wells (MQW) are fabricated by molecular beam epitaxy (MBE). MBE is relatively slow and expensive when compared to alternate thin-film growth techniques used for microelectronics.
Although chemical vapor deposition (CVD) offers a low-cost, high throughput approach to device manufacturing, a lack of suitable, low temperature CVD precursors has hindered its widespread applicability. This is particularly true for Sb-based heterostructures that display important optoelectronic and electronic properties, including InSb, InGaSb, InAsSb, GaAlSb and InSbBi. Volatile and thermally stable Sb precursors would facilitate the chemical vapor deposition of antimonide thin-films, as required for the large scale, controlled production of antimonide based lasers, detectors and microelectronic sensors.
Antimonide materials are attractive for commercial infrared optoelectronic applications. The compositional variety and stoichiometry of III-V compound semiconductors allows for nearly complete coverage of the infrared spectrum. Bandgaps ranging from 2.5 eV in AlP to 0.2 eV in InSb can be achieved by forming strained thin-films with the proper elemental and stoichiometric compositions. Materials of greatest interest include InSbBi and InAs-SbBi
8
for long wavelength (8-12 mm) infrared detectors, InAsSb and InGaSb1° for mid-infrared absorbers in military applications, and InSb/In
1−x
Al
x
Sb
11
light emitting diodes (LEDs) for mid-infrared chemical sensor applications. Many of these materials, however, as mentioned above are metastable compositions that necessitate high-purity films and low processing temperatures.
Antimonides are also of great interest as semiconductor infrared lasers. For instance, a type-II quantum well superlattice laser, comprised of InAsSb active layer with alternating InPSb and AlAsSb cladding layers, provides 3.5 mm emission upon electron injection. Similarly, mid-infrared lasers comprised of InAs/InGaSb/InAs active regions; with lattice-matching to AlSb cladding layers were also demonstrated. The device fabrication requires thin-film processing of elemental aluminum, antimony, gallium and indium to produce both the active and cladding layers, and thereby, presents a significant technological challenge. The inherent physical properties of Ga, Sb and In necessitate low processing temperatures to alleviate inter-diffision, melting, and re-evaporation (i.e., InSb melts at 525° C.). Unfortunately, current Sb CVD sources, such as trimethyl antimony, require processing temperatures in excess of 460° C. to achieve precursor decomposition and useful film growth rates.
SUMMARY OF THE INVENTION
The present invention relates to the substitution of deuterium and/or tritium atoms in place of hydrogen atoms in metal hydrides to yield deutero- and/or tritiato-metal compounds. Substitution of the hydrogen atoms by deuterium and/or tritium eiables the stabilization of some unstable hydrides, including all antimony trihydrides (e.g., stibine SbH
3
) or substituted dihydrides of antimony.
This stabilization improvement is attributable to the hydrogen isotope effect. This effect involves lowering of the ground electronic state (zero point energy) of the deuterium and/or tritium analog compared to the non-deuterated compound. By lowering the ground state, the deuterated and/or tritiated compound is much more stable, i.e., less reactive, than its proteo analog. The theoretical value of k
H
/k
D
is approximately 6.5 for reactions involving C—H bonds. When hydrogen atoms are attached to the heavier elements such as transition metals, this value is frequently much greater than 6.5. Such increase of k
H
/k
D
is attributable to the phenomenon of quantum mechanical tunneling, whereby the height of the activation barrier is effectively lowered due to the ability of the lighter isotope (in this case hydrogen) to tunnel across the barrier of potential energy surface.
In one aspect, the present invention relates to complexes of the type
D
x
MR
y
where:
each D is independently selected from deuterium (
2
1
H) and tritium (
3
1
H) isotope;
M is a metal selected from the group consisting of Group III, IV or V metals and transition metals;
each R is independently selected from C
1
-C
8
alkyl, C, CB perfluoroalkyl, C
1
-C
8
haloalkyl, C
6
-C
10
aryl, C
6
-C
10
perfluoroaryl, C
6
-C
10
haloaryl, C
6
-C
10
cycloalkyl, substituted C
6
-C
10
aryl and halo; and
x and y are each independently from 0 to 6 inclusive.
When R is substituted C
6
-C
10
aryl, the substituents may be independently selected, inter alia, from C
1
-C
8
alkyl, C
1
-C
8
haloalkyl, and halo.
In instances where the cost is not a factor, such as in ion implant applications, tritium may be used instead of deuterium to realize even greater stability than is achievable by the deuterium substitution of the complex.
Another aspect of the invention relates to a metal hydride derivative wherein at least one hydrogen atom is replaced by deuterium (
2
1
H) or tritium (
3
1
H) isotope. The metal hydride's metal constituent is selected from Group III, IV and V metals and transition metals and may for example comprise antimony, aluminum, gallium, tin, germanium, or indium.
The metal hydride of the invention may have the formula MY
n
wherein M is an n-valent metal,
each Y is independently selected from hydrogen, deuterium (
2
1
H) isotope, tritium (
3
1
H) isotope, and halo,
n is at least 2,
with the proviso that at least one Y constituent is either deuterium (
2
1
H) isotope or tritium (
3
1
H).
In such metal hydride, n may be from two to six, inclusive.
Another aspect of the invention relates to metal hydride derivatives of the formula:
D
x
MR
y
wherein:
M is a z-valent metal selected from Group III, IV and V metals and transition metals;
each D is independently selected from hydrogen, deuterium (
2
1
H) isotope and tritium (
3
1
H) isotope;
each R is independently selected from C
1
-C
8
alkyl, C
1
-C
8
perfluoroalkyl, C
1
-C
8
haloalkyl, C
6
-C
10
aryl, C
6
-C
10
perfluoroaryl, C
6
-C
10
haloalkyl, C
6
-C
10
cycloalkyl, substituted C
6
-C
10
aryl and halo;
x is at least one;
x+y=z;
with the proviso at least one D is either deuterium (
2
1
H) isotope or tritium (
3
1
H) isotope.
The in

Affiliated with

Also associated with

Rating

Stable hydride source compositions for manufacture of... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Stable hydride source compositions for manufacture of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stable hydride source compositions for manufacture of... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2618588