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  Germanium compound delivery deviceUSPTO Application #: 20070077733Title: Germanium compound delivery device Abstract: Germanium compounds suitable for use as vapor phase deposition precursors for germanium films are provided. Methods of depositing films containing germanium using such compounds are also provided. Such germanium films are particularly useful in the manufacture of electronic devices. (end of abstract)
Agent: S. Matthew Cairns Rohm And Haas Electronic Materials LLC - Marlborough, MA, US Inventors: Egbert Woelk, Deodatta Vinayak Shenai-Khatkhate USPTO Applicaton #: 20070077733 - Class: 438478000 (USPTO) Related Patent Categories: Semiconductor Device Manufacturing: Process, Formation Of Semiconductive Active Region On Any Substrate (e.g., Fluid Growth, Deposition) The Patent Description & Claims data below is from USPTO Patent Application 20070077733. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application is a divisional of application Ser. No. 10/816,356, filed on Apr. 2, 2004, now allowed, which claims the benefit of provisional application Ser. No. 60/460,791, filed on Apr. 5, 2003, and provisional application Ser. No. 60/513,475, filed on Oct. 22, 2003, and provisional application No. 60/513,476, filed on Oct. 22, 2003. BACKGROUND OF THE INVENTION [0002] The present invention relates generally to the field of germanium compounds. In particular, the present invention relates to the certain germanium compounds suitable for use in vapor deposition processes. [0003] Metal films may be deposited on surfaces, such as non-conductive surfaces, by a variety of means such as chemical vapor deposition ("CVD"), physical vapor deposition ("PVD"), and other epitaxial techniques such as liquid phase epitaxy ("LPE"), molecular beam epitaxy ("MBE"), chemical beam epitaxy ("CBE") and atomic layer deposition ("ALD"). Chemical vapor deposition processes, such as metalorganic chemical vapor deposition ("MOCVD"), deposit a metal layer by decomposing organometallic precursor compounds at elevated temperatures, i.e., above room temperature, either atmospheric pressure or at reduced pressures. A wide variety of metals may be deposited using such CVD or MOCVD processes. [0004] For semiconductor and electronic device applications, these organometallic precursor compounds must be highly pure and be substantially free of detectable levels of both metallic impurities, such as silicon and zinc, as well as oxygenated impurities. Oxygenated impurities are typically present from the solvents used to prepare such organometallic compounds, and are also present from other adventitious sources of moisture or oxygen. [0005] For certain applications where high speed and frequency response of an electronic device is desired, silicon-only devices, e.g. silicon bipolar transistors, perform marginally and the introduction of germanium is necessary to obtain the desired functionality. In a heterojunction bipolar transistor ("HBT"), a thin silicon-germanium layer is grown as the base of a bipolar transistor on a silicon wafer. The silicon-germanium HBT has significant advantages in speed, frequency response, and gain when compared to a conventional silicon bipolar transistor. The speed and frequency response of a silicon-germanium HBT are comparable to more expensive gallium-arsenide HBTs. [0006] The higher gain, speeds, and frequency response of silicon-germanium HBTs have been achieved as a result of certain advantages of silicon-germanium not available with pure silicon, for example, narrower band gap and reduced resistivity. Silicon-germanium may be epitaxially grown on a silicon substrate using conventional silicon processing and tools. This technique allows one to engineer device properties such as the energy band structure and carrier mobility. For example, it is known in the art that grading the concentration of germanium in the silicon-germanium base builds into the HBT device an electric field or potential gradient, which accelerates the carriers across the base, thereby increasing the speed of the HBT device compared to a silicon-only device. A common method for fabricating silicon and silicon-germanium devices is by CVD. A reduced pressure chemical vapor deposition technique ("RPCVD") used to fabricate the HBT device allows for a controlled grading of germanium concentration across the base layer as well as precise control over the doping profile. [0007] Germane (GeH.sub.4) is the conventional precursor for germanium deposition. Germane is a gas under standard conditions and is difficult to handle. As germane is toxic, processes employing germane require extensive safety procedures and equipment. Germane typically requires film growth temperatures of approximately 500.degree. C. for thermal CVD applications. Such decomposition temperatures are not always suitable, such as in applications where there is a need for lower temperatures, e.g. 200.degree. C. Other CVD applications require higher growth temperatures, e.g. 700-1100.degree. C., which cause germane to break up prematurely which, in turn, leads to the formation of particles and a reduction in metal film growth rates. A further problem with germanium precursors arises in silicon-germanium deposition when a relatively stable silicon precursor and a relatively unstable germanium precursor (germane) are used to deposit a silicon-germanium film, the differences in precursor stability makes control of the silicon-germanium composition difficult. [0008] U.S. Patent Application No. 2003/0111013 (Oosterlaken et al.) discloses an apparatus for the deposition of silicon germanium layers. This application discloses certain source compounds for the vapor deposition of germanium, such as mono-, di- tri- and tetra-chlorogermanes. Such compounds may not be suitable for all germanium vapor deposition applications as their decomposition temperatures may be too low. For example, monochlorogermane is known to decompose at temperatures as low as 25.degree. C. [0009] There remains a need for germanium precursors that offer an optimized deposition of germanium-containing films at various growth temperatures. Such growth temperatures determine the properties of the germanium-containing film. A limitation in growth temperature limits the full exploitation of the capabilities of a germanium-containing film. There remains a need for germanium precursors for CVD that are safer to handle. SUMMARY OF THE INVENTION [0010] The present inventors have surprisingly found that the above limitations on the deposition of germanium by CVD can be remedied. The present invention provides a method of depositing a film containing germanium on a substrate including the steps of: a) conveying two or more germanium compounds in a gaseous phase to a deposition chamber containing the substrate, wherein a first germanium compound is a halogermanium compound of the formula X.sup.1.sub.4-aGeR.sub.a, wherein a=0-3, each X.sup.1 is independently a halogen, and each R is independently chosen from H, alkyl, alkenyl, alkynyl, aryl, and NR.sup.4R.sup.6, wherein each R.sup.4 and R.sup.6 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl, and wherein a second germanium compound has the formula wherein each R.sup.1 and R.sup.2 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl; each R.sup.3 is independently chosen from alkyl, alkenyl, alkynyl and aryl; X is halogen; a'=0-4; b'=0-4; c'=0-3; d'=0-4 and a'+b'+c'+d'=4; provided that a'+b'.ltoreq.3 when X.sup.1=Cl, R=H, and X=Cl; b) decomposing the two or more germanium compounds in the deposition chamber; and c) depositing the film comprising germanium on the substrate. [0011] Further, the present invention provides a method of manufacturing an electronic device including the step of depositing a film containing germanium on a substrate wherein the film including the steps of: a) conveying two or more germanium compounds in a gaseous phase to a deposition chamber containing the substrate, wherein a first germanium compound is a halogermanium compound of the formula X.sup.1.sub.4-aGeR.sub.a, wherein a=0-3, each X.sup.1 is independently a halogen, and each R is independently chosen from H, alkyl, alkenyl, alkynyl, aryl, and NR.sup.4R.sup.6, wherein each R.sup.4 and R.sup.6 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl, and wherein a second germanium compound has the formula wherein each R.sup.1 and R.sup.2 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl; each R.sup.3 is independently chosen from alkyl, alkenyl, alkynyl and aryl; X is halogen; a'=0-4; b'=0-4; c'=0-3; d'=0-4 and a'+b'+c'+d'=4; provided that a'+b'.ltoreq.3 when X.sup.1 =Cl, R=H, and X=Cl; b) decomposing the two or more germanium compounds in the deposition chamber; and c) depositing the film comprising germanium on the substrate. [0012] The present invention also provides a composition including two or more germanium compounds; wherein a first germanium compound is a halogermanium compound of the formula X.sup.1.sub.4-aGeR.sub.a, wherein a=0-3, each X.sup.1 is independently a halogen, and each R is independently chosen from H, alkyl, alkenyl, alkynyl, aryl, and NR.sup.4R.sup.6, wherein each R.sup.4 and R.sup.6 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl, and wherein a second germanium compound has the formula wherein each R.sup.1 and R.sup.2 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl; each R.sup.3 is independently chosen from alkyl, alkenyl, alkynyl and aryl; X is halogen; a'=0-4; b'=0-4; c'=0-3; d'=0-4 and a'+b'+c'+d'=4; provided that a'+b'.ltoreq.3 when X.sup.1 =Cl, R=H, and X=Cl. [0013] Still further, the present invention provides a vapor delivery device suitable for feeding a fluid stream saturated with a germanium compound suitable for depositing a film containing germanium to a chemical vapor deposition system including a vessel having an elongated cylindrical shaped portion having an inner surface having a cross-section, a top closure portion and a bottom closure portion, the top closure portion having an inlet opening for the introduction of a carrier gas and an outlet opening, the elongated cylindrical shaped portion having a chamber containing two or more germanium compounds; the inlet opening being in fluid communication with the chamber and the chamber being in fluid communication with the outlet opening. In one embodiment, the two or more germanium compounds include a first halogermanium compound of the formula X.sup.1 .sub.4-aGeR.sub.a, wherein a=0-3, each X.sup.1 is independently a halogen, and each R is independently chosen from H, alkyl, alkenyl, alkynyl, aryl, and NR.sup.4R.sup.6, wherein each R.sup.4 and R.sup.6 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl, and a second germanium compound of the formula wherein each R.sup.1 and R.sup.2 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl; each R.sup.3 is independently chosen from alkyl, alkenyl, alkynyl and aryl; X is halogen; a'=0-4; b'=0-4; c'=0-3; d'=0-4 and a'+b'+c'+d'=4; provided that a'+b.varies..ltoreq.3 when X.sup.1=Cl, R=H, and X=Cl. [0014] Another embodiment of the present invention is an apparatus for vapor deposition of metal films including one or more devices for feeding a fluid stream including two or more germanium compounds, such as those described above. DETAILED DESCRIPTION OF THE INVENTION [0015] As used throughout this specification, the following abbreviations shall have the following meanings, unless the context clearly indicates otherwise:.degree. C.=degrees centigrade; mol =moles; g=gram; ca.=approximately; and .mu.m=micron=micrometer. "Halogen" refers to fluorine, chlorine, bromine and iodine and "halo" refers to fluoro, chloro, bromo and iodo. Likewise, "halogenated" refers to fluorinated, chlorinated, brominated and iodinated. "Alkyl" includes linear, branched and cyclic alkyl. Likewise, "alkenyl" and "alkynyl" include linear, branched and cyclic alkenyl and alkynyl, respectively. The term "SiGe" refers to silicon-germanium. As used herein, "CVD" is intended to include all forms of chemical vapor deposition such as MOCVD, MOVPE, OMVPE, OMCVD and RPCVD. The articles "a" and "an" refer to the singular and the plural. [0016] Unless otherwise noted, all amounts are percent by weight and all ratios are molar ratios. All numerical ranges are inclusive and combinable in any order except where it is clear that such numerical ranges are constrained to add up to 100%. [0017] The present invention provides a method of depositing a film containing germanium on a substrate including the steps of: a) conveying two or more germanium compounds in a gaseous phase to a deposition chamber containing the substrate, wherein a first germanium compound is a halogermanium compound of the formula X.sup.1.sub.4-aGeR.sub.a, wherein a=0-3, each X.sup.1 is independently a halogen, and each R is independently chosen from H, alkyl, alkenyl, alkynyl, aryl, and NR.sup.4R.sup.6, wherein each R.sup.4 and R.sup.6 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl, and wherein a second germanium compound has the formula wherein each R.sup.1 and R.sup.2 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl; each R.sup.3 is independently chosen from alkyl, alkenyl, alkynyl and aryl; X is halogen; a'=0-4; b'=0-4; c'=0-3; d'=0-4 and a'+b'+c'+d'=4; provided that a'+b'.ltoreq.3 when X.sup.1=Cl, R=H, and X=Cl; b) decomposing the two or more germanium compounds in the deposition chamber; and c) depositing the film comprising germanium on the substrate. In one embodiment, the second germanium compound is an alkyl germane. Exemplary alkyl germanes include, without limitation, those compounds having the above formula where a'=c'=0, d'=2-3, and b'=1-2. In a further embodiment, the alkyl germanium compound is a heteroleptic alkyl germanium compound. By "heteroleptic alkyl germanium compound" is meant a germanium compound having mixed alkyl groups, i.e., a germanium compound having two or more alkyl groups where at least two of the alkyl groups are different. Exemplary heteroleptic alkyl germanium compounds include those of the formula R.sup.5.sub.zGeH.sub.y; wherein each R.sup.5 is independently chosen from alkyl, alkenyl, alkynyl and aryl; z=2-3; and y=1-2. [0018] In another embodiment, at least two halogermanium compounds are used. As used herein, the term "halogermanium compound" refers to any germanium compound having one or more halogens bonded directly to the germanium. The present halogermanium compounds may have a wide variety of other groups bonded to the germanium, provided that at least one halogen is bonded to the germanium. It will be clear to those skilled in the art that three, four or more different germanium compounds, particularly halogermanium compounds, may be advantageously used in the present invention. [0019] A wide variety of halogermanium compounds may be used, such as, but not limited to, tetrahalogermanes and halogermanium compounds of the formula X.sup.1.sub.4-aGeR.sub.a, wherein each R is independently chosen from H, alkyl, alkenyl, alkynyl, aryl and NR.sup.1R.sup.2; R.sup.1 and R.sup.2 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl; each X.sup.1 is independently halogen; and a=0-3. The tetrahalogermanes have the formula GeX.sup.1.sub.4, wherein each X is independently a halogen. When two or more halogens are present in the halogermanium compounds, such halogens may be the same or different. [0020] A wide variety of alkyl, alkenyl and alkynyl groups may be used for R, R.sup.1 and R.sup.2. Suitable alkyl groups include, without limitation, (C.sub.1-C.sub.12)alkyl, typically (C.sub.1-C.sub.6)alkyl and more typically (C.sub.1-C.sub.4)alkyl. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, hexyl, and cyclohexyl. More typically, suitable alkyl groups include ethyl, iso-propyl, and tert-butyl. Suitable alkenyl groups include, without limitation, (C.sub.2-C.sub.12)alkenyl, typically (C.sub.2-C.sub.6)alkenyl and more typically (C.sub.2-C.sub.4)alkenyl. Exemplary alkenyl groups include vinyl, allyl, methallyl and crotyl. Typical alkynyl groups include, without limitation, (C.sub.2-C.sub.12)alkynyl, typically (C.sub.2-C.sub.6) alkynyl and more typically (C.sub.2-C.sub.4)alkynyl. Suitable aryl groups are (C.sub.6-C.sub.10)aryl, including, but not limited to, phenyl, tolyl, xylyl, benzyl and phenethyl. When two or more alkyl, alkenyl or alkynyl groups are present, such groups may be the same or different. [0021] Typical amino (NR.sup.1R.sup.2) groups for R include, but are not limited to, dimethylamino, diethylamino, di-iso-propylamino, ethylmethylamino, iso-propylamino, and tert-butylamino. However, other suitable amino groups may be used. Any of the above alkyl, alkenyl, alkynyl or aryl groups of R, R.sup.1 and R.sup.2 may optionally be substituted with one or more amino (NR.sup.4R.sup.6) groups, wherein R.sup.4 and R.sup.6 are independently chosen from H, alkyl, alkenyl, alkynyl and aryl. By "substituted" it is meant that one or more hydrogens on the alkyl, alkenyl, alkynyl or aryl group is replaced with one or more NR.sup.4R6 groups. Exemplary alkyl substituted with NR.sup.4R.sup.6 groups include, without limitation, dimethylamino-methyl ((CH.sub.3).sub.2N--CH.sub.2-), dimethylamino-ethyl ((CH.sub.3).sub.2N--C.sub.2H.sub.4-), diethylamino-ethyl ((C.sub.2H.sub.5).sub.2N--C.sub.2H.sub.4-), dimethylamino-propyl ((CH.sub.3).sub.2N--C.sub.3H.sub.6-), and diethylamino-propyl ((C.sub.2H.sub.5).sub.2N--C.sub.3H.sub.6-). Continue reading... Full patent description for Germanium compound delivery device Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Germanium compound delivery device patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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