Br2SbCH3 a solid source ion implant and CVD precursor

Details Br2SbCH3 a solid source ion implant and CVD precursor Br2SbCH3 a solid source ion implant and CVD precursor

2002-08-07

2004-07-27

Nazario-Gonzalez, Porfirio (Department: 1621)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

To form ohmic contact to semiconductive material

C427S523000, C427S587000, C427S593000, C438S604000, C556S070000

Reexamination Certificate

active

06767830

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a novel solid source antimony precursor, and more particularly, to Br
2
SbCH
3
and method of synthesizing same for use in ion implantation and deposition.
2. Description of the Related Art
The reduction in critical dimensions necessary for continued gains in dynamic random access memory (DRAM) circuit density will require a number of fundamental changes from current practice, relative to the techniques and source materials employed in current manufacturing practice. As geometries of such DRAM devices decrease below 0.35 micrometer, a corresponding reduction is necessary in the size of p
dopant layer thicknesses and in the associated dopant concentrations.
The mobility of lightweight p-type and n-type dopants is too high, even with reduced thermal budgets, to accommodate the increased stringency of future implant requirements. Thus, it will be necessary to develop dopants that can be utilized in very shallow p
layers. This implies that traditional dopants such as boron (p-type) and phosphorus (n-type) will have to be replaced due to their high mobility in silicon (which results in a breakdown of the junction, even with reduced thermal budgets).
Dopants with significantly greater size and mass, will need to be used to improve control of ion throughput and to reduce channeling effects in the fabricated structures. A logical choice for an n-type dopant is antimony, due to its greater size and mass, that provide superior diffusion characteristics relative to traditional implant species. These properties make it possible to use lower implant energies and more advantageous geometries when depositing the shallow p
junctions that are critical to DRAM storage density increases.
Currently solid species, such as Sb
2
O
3
and SbF
3
are used to generate ion beams for ion implantation but have been found to be problematic. For example, Sb
2
O
3
requires high temperatures to volatize, leading to particle formation from recondensation or entrainment within the ion implanter. The addition of fluorine may cause additional diffusion of which often results in contamination of the well region and loss of threshold voltage control in the resulting devices.
Chemical vapor deposition (CVD) offers a low-cost, high throughput approach to device manufacturing. However, 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. Unfortunately, current Sb CVD sources require processing temperatures in excess of 460° C. to achieve precursor decomposition and useful film growth rates. 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.
Thus, suitable volatile antimony precursors are currently unavailable. Accordingly, the art is in need of new source compositions of antimony for ion implant and CVD applications.
SUMMARY OF THE INVENTION
The present invention relates to novel antimony compounds and method of synthesizing same. The novel antimony compounds of the invention may have the formula:
X
2
SbCH
3
wherein each X is a halogen and independently selected from the group consisting of F, Cl, Br and I, and preferably the halogen is Br. It has been expectedly discovered that the novel antimony compounds, having only one carbon molecule, exhibit high volatility.
In another aspect, the invention relates to a method of synthesizing the antimony compounds of the invention comprising:
combining a trihalide antimony compound with trimethylantimony;
heating the trihalide antimony compound and trimethylantimony at a temperature of from 30° C. to about 90° C. for the a sufficient amount of time to at least melt the trihalide antimony compound and to form a X
2
SbCH
3
product; and
purifying the X
2
SbCH
3
to form a crystalline product.
Preferably, the trihalide antimony compound and the trimethylantimony compound are combined and heated without a solvent at a temperature from about 60° to 75° C.
In yet another aspect, the invention relates to a method of depositing antimony on a substrate from an antimony-containing precursor therefor, comprising using as a precursor an antimony molecule of the formula:
X
2
SbCH
3
wherein each X is a halogen independently selected from the group consisting of F, Cl, Br and I, and preferably the halogen is Br.
In such a method, the antimony compound of the invention may be deposited by a deposition process including, but not limited to, chemical vapor deposition, assisted chemical vapor deposition (e.g., laser, light, plasma, ion, etc.), ion implantation, molecular beam epitaxy, diffusion and rapid thermal processing.
Other aspects and features of the invention will be more fully apparent from the ensuing disclosure and appended claims.


REFERENCES:
Malish et al., Chem. Ber., vol. 108, pp. 700-715 (1975).*
L. Wang, et al., Semiconductor International, Next Generation Dopont Development and Characterization, Oct. 1, 1998.
H. Althaus, et al., Organometallics 2001, 20, 586-589, Syntheses and Chemistry of Methylantimony and Methylbismuth Dihalides: An Extended Two-Dimensional Framework in the Crystal Structure of...
Alan Berry, “Encyclopedia of Inorganic Chemistry” vol. 1 “Antimony Organometallic Chemistry” p. 176-190.
Ates, Mustafa et al., “Alkylantimondichloride und—bromide”,Journal of Organometallic Chemistry, 364 (1989) pp. 67-71.
Breunig, Hans Joachim et al., “Strukturen und Reaktionen von Methylantimondihalogeniden und Versuche zur Darstellung von Methylantimon”Journal of Organometallic Chemistry, 470 (1994) pp. 87-92.

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