JP2019212677A - Organometallic molecular beam epitaxy method and apparatus - Google Patents
Organometallic molecular beam epitaxy method and apparatus Download PDFInfo
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本発明は分子線エピタキシーに関し、特に分子線のための原料として有機金属を使用する分子線エピタキシー方法及び装置に関する。 The present invention relates to molecular beam epitaxy, and more particularly to a molecular beam epitaxy method and apparatus that uses an organic metal as a raw material for molecular beams.
遷移金属を含む窒化物は、金属や超伝導をはじめとする実用上有用な種々の物性を示す物質群であるが、酸化物等の他の無機物質群に比べると、合成が困難であるため物質開拓が遅れている。また、本発明をこれに限定する意図はないが、特に、２種類以上の金属元素を含んだ多成分系遷移金属窒化物の合成と物質開拓は著しく遅れている。 Nitrides containing transition metals are a group of substances that exhibit various practically useful physical properties including metals and superconductivity, but they are difficult to synthesize compared to other inorganic substances such as oxides. Material development is delayed. In addition, the present invention is not intended to be limited to this, but in particular, synthesis and material development of multi-component transition metal nitrides containing two or more kinds of metal elements are significantly delayed.
薄膜化手法は、窒化物合成の有力な手法の一つである。実際、広く実用化されているワイドギャップ半導体である窒化ガリウムとその関連窒化物は、１９８０年代後半から始まった薄膜化手法による合成が先行し、単結晶ウエハーは２０００年代になってようやく実現した。種々の薄膜作製手法の中でも、薄膜を構成する元素を個別に供給し原子層レベルで薄膜成長を制御できる分子線エピタキシー法は、高品質薄膜を得ることができる手法の一つである。電子由来のさまざまな物性を発現する遷移金属窒化物の薄膜成長において、高融点・低蒸気圧の遷移金属原料の供給は、その供給レートの不安定さが常に問題となり、良質な試料作製を困難なものとしてきた(非特許文献１)。特に、２種類以上の金属を含んだ多成分系遷移金属窒化物の合成においては、薄膜試料の組成比の制御に深刻な影響を与える。 The thinning technique is one of the effective techniques for nitride synthesis. In fact, gallium nitride, which is a wide-gap semiconductor widely used in practice, and related nitrides were first synthesized by a thinning technique that began in the late 1980s, and single crystal wafers were finally realized in the 2000s. Among various thin film manufacturing techniques, the molecular beam epitaxy method that can individually control the thin film growth at the atomic layer level by supplying the elements constituting the thin film is one of the techniques for obtaining a high quality thin film. In the growth of transition metal nitride thin films that exhibit various physical properties derived from electrons, the supply of transition metal raw materials with high melting points and low vapor pressures has always been a problem with the instability of the supply rate, making it difficult to produce high-quality samples. (Non-Patent Document 1). In particular, in the synthesis of a multicomponent transition metal nitride containing two or more kinds of metals, it seriously affects the control of the composition ratio of the thin film sample.
分子線エピタキシー（molecular beam epitaxy、ＭＢＥ）法によって遷移金属窒化物薄膜を作製する際には、遷移金属の原料供給は、電子ビーム蒸着やエフュージョンセル(effusion cell)を用いて、原料である遷移金属の固体原料を加熱して蒸発させるのが一般的である。この手法では、低蒸気圧の遷移金属の原料供給速度の上限に限界があり、かつ、その供給速度の時間変化が薄膜成長に著しく大きな影響を及ぼす程に大きい。たとえば特許文献１には、遷移金属（具体的にはＴｉ）を電子銃からの電子線により加熱して遷移金属の分子線を発生させて、これとプラズマ化により発生された原子状窒素との反応により基板上に遷移金属窒化物薄膜を生成するにあたって、供給されている分子線の量をモニタしないオープンループ制御を行った場合には、生成される遷移元素窒化物の組成比がばらつき、それにより作成された薄膜が所望の特性を有しなくなる場合があることが説明されている。 When producing a transition metal nitride thin film by molecular beam epitaxy (MBE) method, the transition metal source material is supplied by using electron beam evaporation or an effusion cell. In general, the solid raw material is heated and evaporated. In this method, there is a limit to the upper limit of the raw material supply rate of the low vapor pressure transition metal, and the change over time in the supply rate is so large that it significantly affects thin film growth. For example, Patent Document 1 discloses that a transition metal (specifically, Ti) is heated by an electron beam from an electron gun to generate a molecular beam of the transition metal and atomic nitrogen generated by the plasma formation. When generating a transition metal nitride thin film on a substrate by reaction, if open loop control is performed without monitoring the amount of molecular beam being supplied, the composition ratio of the generated transition element nitride varies. It is explained that the thin film produced by the above may not have the desired characteristics.
このため、先行研究では、遷移金属の供給速度を制御するために、遷移金属の蒸発量を電子衝撃発光分光装置（ＥＩＥＳ）により検出し、電子ビーム蒸着装置やエフュージョンセルの加熱温度に常時フィードバックするシステムが開発された(特許文献１、非特許文献２)。しかしながら、このシステムでは、ＥＩＥＳをＭＢＥ装置内に取り付ける必要があり、装置の大型化が避けられない。また、このＥＩＥＳは非常に高価な装置である点からも、使用できる局面・対象が限定されてしまう。このような問題は遷移金属に限られるものではなく、典型金属の場合でも同様であり、金属元素一般について、その化合物を、大規模・高価な装置や複雑な制御を要することなく、安定した組成で成膜することが望まれる。 For this reason, in previous studies, in order to control the supply rate of transition metal, the amount of transition metal evaporation is detected by an electron impact emission spectrometer (EIES), and is always fed back to the heating temperature of the electron beam evaporation system or effusion cell. A system was developed (Patent Document 1, Non-Patent Document 2). However, in this system, it is necessary to mount the EIES in the MBE device, and the size of the device cannot be avoided. Moreover, the aspect and object which can be used will also be limited from the point that this EIES is a very expensive apparatus. Such problems are not limited to transition metals, and the same applies to typical metals. For metal elements in general, the compounds can be made stable without requiring large-scale and expensive equipment or complicated control. It is desirable to form a film with this.
本発明の課題は、遷移金属等の金属原料を安定して供給し、かつその供給速度を広いレンジで変化することができるようにすることで、大型・高価な装置を使用することなく、遷移金属窒化物等の金属化合物の高品質の薄膜を作成できるようにするＭＢＥ方法及び装置を提供することにある。 The object of the present invention is to stably supply a metal raw material such as a transition metal and to change the supply speed in a wide range, so that a transition can be made without using a large and expensive device. An object of the present invention is to provide an MBE method and apparatus capable of producing a high-quality thin film of a metal compound such as metal nitride.
本発明の一側面によれば、分子線エピタキシーのための金属の原料として有機金属を供給する分子線エピタキシー方法が与えられる。
ここで、前記金属の窒化物を合成してよい。
また、前記有機金属と同時に原子状窒素を供給してよい。
また、室温で液体または気体である前記有機金属を気化させてから供給してよい。
また、前記金属は、Ｔｉ、Ｍｇ、Ａｌ、Ｖ、Ｃｒ、Ｚｎ、Ｇａ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｒｕ、Ｃｄ、Ｓｎ、Ｈｆ、Ｔａ、Ｗ、Ｉｒ、Ｌａ、Ｅｒからなる群から選択されてよい。
また、前記有機金属は窒素を含んでよい。
また、前記有機金属は、Tetrakis dimethylamino titanium、Tetrakis diethylamino titanium、Tetrakis ethylmethylamino titanium、Bis(ethylcyclopentadienyl)magnesium、Bis(n-propylcyclopentadienyl)magnesium、Tri-i-butylaluminum、Triethylaluminum、Trimethylaluminum、Tetrakis(diethylamino)vanadium(IV)、Bis(ethylbenzene)chromium、Bis(i-propylcyclopentadienyl)chromium、Diethylzinc、Dimethylzinc、Triethylgallium、Tris(butylcyclopentadienyl)yttrium、Tetrakis(diethylamino)zirconium、Tris(ethylmethylamido)(tert-butylimido)niobium(V)、Tris(diethylamido)(tert-butylimido)niobium(V)、Bis(t-butylimido)bis(dimethylamino) molybdenum(VI)、Bis(ethylcyclopentadienyl)ruthenium(II)、Dimethylcadmium、Tetramethyltin、Tetraethyltin、Tetrakis(diethylamino)hafnium、Tetrakis(ethylmethylamino)hafnium、(t-Butylimido)tris(diethylamino)tantalum(V)、Bis(t-butylimido)bis(dimethylamido) tungsten(VI)、1-Ethylcyclopentadienyl-1,3-cyclohexadieneiridium(I)、Tris(i-propylcyclopentadienyl)lanthanum、及びTris(n-butylcyclopentadienyl)erbiumからなる群から選択されてよい。
また、前記金属と異なる金属の原料を前記有機金属と同時に供給してよい。
本発明の他の側面によれば、分子線エピタキシーにより基板上に金属の化合物の成膜を行う分子線エピタキシー装置であって、内部で前記成膜が行われる真空槽と、気化された有機金属を供給する有機金属供給部と、前記有機金属供給部から供給された前記有機金属の気体を前記真空槽内に置かれた前記基板に供給するガスソースセルとを設けた、分子線エピタキシー装置が与えられる。
ここで、前記基板を加熱する基板加熱機構が設けられてよい。
また、前記金属の化合物は前記金属の窒化物であってよい。
また、前記ガスソースセルによる前記有機金属の供給と同時に原子状態の窒素を前記基板に供給してよい。
また、前記真空槽内に置かれた前記基板と前記ガスソースセルとの間の距離を変化させることができるようにしてよい。
また、分子線エピタキシーの原料として前記有機金属と前記有機金属以外の物質とを前記ガスソースセルから選択的に前記基板に供給するように構成されるとともに、前記基板へ前記原料が吸着されにくい程、前記基板と前記ガスソースセルとの間の距離を小さくするように設定できるようにしてよい。
また、前記金属は、Ｔｉ、Ｍｇ、Ａｌ、Ｖ、Ｃｒ、Ｚｎ、Ｇａ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｒｕ、Ｃｄ、Ｓｎ、Ｈｆ、Ｔａ、Ｗ、Ｉｒ、Ｌａ、Ｅｒからなる群から選択されてよい。
また、前記有機金属は、Tetrakis dimethylamino titanium、Tetrakisdiethylaminotitanium、Tetrakisethylmethylaminotitanium、Bis(ethylcyclopentadienyl)magnesium、Bis(n-propylcyclopentadienyl)magnesium、Tri-i-butylaluminum、Triethylaluminum、Trimethylaluminum、Tetrakis(diethylamino)vanadium(IV)、Bis(ethylbenzene)chromium、Bis(i-propylcyclopentadienyl)chromium、Diethylzinc、Dimethylzinc、Triethylgallium、Tris(butylcyclopentadienyl)yttrium、Tetrakis(diethylamino)zirconium、Tris(ethylmethylamido)(tert-butylimido)niobium(V)、Tris(diethylamido)(tert-butylimido)niobium(V)、Bis(t-butylimido)bis(dimethylamino) molybdenum(VI)、Bis(ethylcyclopentadienyl)ruthenium(II)、Dimethylcadmium、Tetramethyltin、Tetraethyltin、Tetrakis(diethylamino)hafnium、Tetrakis(ethylmethylamino)hafnium、(t-Butylimido)tris(diethylamino)tantalum(V)、Bis(t-butylimido)bis(dimethylamido) tungsten(VI)、1-Ethylcyclopentadienyl-1,3-cyclohexadieneiridium(I)、Tris(i-propylcyclopentadienyl)lanthanum、及びTris(n-butylcyclopentadienyl)erbiumからなる群から選択されてよい。
本発明の更に他の属面によれば、前記基板に対して前記金属と異なる金属の原料を前記有機金属と同時に供給する機構を有する、上記何れかの分子線エピタキシー装置が与えられる。
According to one aspect of the present invention, there is provided a molecular beam epitaxy method for supplying an organic metal as a metal source for molecular beam epitaxy.
Here, the metal nitride may be synthesized.
Further, atomic nitrogen may be supplied simultaneously with the organic metal.
Further, the organic metal that is liquid or gas at room temperature may be vaporized before being supplied.
The metal is selected from the group consisting of Ti, Mg, Al, V, Cr, Zn, Ga, Y, Zr, Nb, Mo, Ru, Cd, Sn, Hf, Ta, W, Ir, La, Er. May be.
The organic metal may contain nitrogen.
Further, the organometal is Tetrakis dimethylamino titanium, Tetrakis diethylamino titanium, Tetrakis ethylmethylamino titanium, Bis (ethylcyclopentadienyl) magnesium, Bis (n-propylcyclopentadienyl) magnesium, Tri-i-butylaluminum, Triethylaluminum, Trimethylaluminum, Tetrakis (diethylamino) vanadium (IV). ), Bis (ethylbenzene) chromium, Bis (i-propylcyclopentadienyl) chromium, Diethylzinc, Dimethylzinc, Triethylgallium, Tris (butylcyclopentadienyl) yttrium, Tetrakis (diethylamino) zirconium, Tris (ethylmethylamido) (tert-butylimido) niobium (V), Tris ( diethylamido) (tert-butylimido) niobium (V), Bis (t-butylimido) bis (dimethylamino) molybdenum (VI), Bis (ethylcyclopentadienyl) ruthenium (II), Dimethylcadmium, Tetramethyltin, Tetraethyltin, Tetrakis (diethylamino) hafnium, Tetrakis ( ethylmethylamino) hafnium, (t-Butylimido) tris (diethylamino) tantalum (V), Bis (t-butylimido) bis (dimethylamido) tungsten (VI), 1-Ethylcyclopentadienyl-1,3-cyclohexadieneiridium (I), Tris (i- propylcyclopentadienyl) lant It may be selected from the group consisting of hanum and Tris (n-butylcyclopentadienyl) erbium.
Further, a metal raw material different from the metal may be supplied simultaneously with the organic metal.
According to another aspect of the present invention, there is provided a molecular beam epitaxy apparatus for depositing a metal compound on a substrate by molecular beam epitaxy, wherein a vacuum chamber in which the film deposition is performed, and a vaporized organic metal A molecular beam epitaxy apparatus comprising: an organic metal supply unit that supplies gas; and a gas source cell that supplies the organic metal gas supplied from the organic metal supply unit to the substrate placed in the vacuum chamber. Given.
Here, a substrate heating mechanism for heating the substrate may be provided.
The metal compound may be a nitride of the metal.
Further, simultaneously with the supply of the organic metal by the gas source cell, nitrogen in an atomic state may be supplied to the substrate.
Further, a distance between the substrate placed in the vacuum chamber and the gas source cell may be changed.
Further, the organic metal and a material other than the organic metal are selectively supplied from the gas source cell to the substrate as a molecular beam epitaxy raw material, and the raw material is less likely to be adsorbed to the substrate. The distance between the substrate and the gas source cell may be set to be small.
The metal is selected from the group consisting of Ti, Mg, Al, V, Cr, Zn, Ga, Y, Zr, Nb, Mo, Ru, Cd, Sn, Hf, Ta, W, Ir, La, Er. May be.
The organometals include Tetrakis dimethylamino titanium, Tetrakisdiethylaminotitanium, Tetrakisethylmethylaminotitanium, Bis (ethylcyclopentadienyl) magnesium, Bis (n-propylcyclopentadienyl) magnesium, Tri-i-butylaluminum, Triethylaluminum, Trimethylaluminum, Tetrakia (is) ethylbenzene) chromium, Bis (i-propylcyclopentadienyl) chromium, Diethylzinc, Dimethylzinc, Triethylgallium, Tris (butylcyclopentadienyl) yttrium, Tetrakis (diethylamino) zirconium, Tris (ethylmethylamido) (tert-butylimido) niobium (V), Tris (diethylamido) (tert -butylimido) niobium (V), Bis (t-butylimido) bis (dimethylamino) molybdenum (VI), Bis (ethylcyclopentadienyl) ruthenium (II), Dimethylcadmium, Tetramethyltin, Tetraethyltin, Tetrakis (diethylamino) hafnium, Tetrakis (ethylmethylamino) hafnium, (t-Butylimido) tris (diethylamino) tantalum (V), Bis (t-butylimido) bis (dimethylamido) tungsten (VI), 1-Ethylcyclopentadienyl-1,3-cyclohexadieneiridium (I), Tris (i-propylcyclopentadienyl) lanthanu m, and may be selected from the group consisting of Tris (n-butylcyclopentadienyl) erbium.
According to yet another aspect of the present invention, there is provided any one of the molecular beam epitaxy apparatuses described above having a mechanism for supplying a metal source different from the metal to the substrate simultaneously with the organic metal.
本発明によれば、遷移金属窒化物のＭＢＥ法を用いた薄膜成長を行うにあたって、遷移金属の原料として高融点・低蒸気圧の物質を使用していたために引き起こされていた不安定で、かつ供給速度が遅いという原料供給の問題が改善される。 According to the present invention, when performing thin film growth of transition metal nitride using MBE method, it is unstable caused by using a material having a high melting point and low vapor pressure as a raw material for transition metal, and The problem of raw material supply that the supply speed is slow is improved.
本願発明者による研究の結果、上述したところの遷移金属窒化膜の品質のばらつきは、遷移金属をＭＢＥの原料としてそのまま使用した場合に、多くの遷移金属が高融点・低蒸気圧（例えば金属Ｔｉの融点は１６６８℃）であるために、多くの遷移金属の蒸発が不安定であることに起因するという知見を得た。また、高融点・低蒸気圧であることから、成膜対象への遷移金属の供給速度も低いものになってしまう。本願発明者はここで遷移金属の有機化合物（有機遷移金属）の多くは液体であり、このような液体は図２に示すように対応する遷移金属等の固体原料に比べて融点がはるかに低く、しかも蒸気圧がはるかに高いことに着目した。この知見に基づいて、本願発明者は、簡便でかつより精度の高い供給量制御と、より広いレンジで原料供給速度を変化させることが可能な遷移金属の原料供給の手法として、遷移金属を含んだ有機金属を原料として用いる有機金属ＭＢＥ方法を発明するに至った。 As a result of the research by the inventors of the present application, the above-described variation in the quality of the transition metal nitride film is that many transition metals have a high melting point and low vapor pressure (for example, metal Ti The melting point of 1668 ° C. was found to be due to unstable evaporation of many transition metals. Moreover, since the melting point is low and the vapor pressure is low, the supply rate of the transition metal to the film formation target is also low. The inventor of the present application is that many of transition metal organic compounds (organic transition metals) are liquids, and such liquids have a much lower melting point than the corresponding solid materials such as transition metals as shown in FIG. I also focused on the much higher vapor pressure. Based on this knowledge, the inventor of the present application includes a transition metal as a method of supplying a transition metal with a simple and more accurate supply amount control and a material supply speed of a transition metal capable of changing a raw material supply speed in a wider range. The inventors have invented an organic metal MBE method using an organic metal as a raw material.
本発明の一実施態様によれば、この原料として、常温常圧で液体であって、蒸気圧が高い、遷移金属等の金属を含んだ有機金属を原料として用いる。この有機金属原料は、遷移金属窒化物を合成するため、金属元素と化学結合を形成しやすい酸素が分子内に存在しない有機金属分子が好ましく、また遷移金属イオンの周りに窒素原子が配位した有機金属分子が好ましい。もちろん、窒素を含んでいない有機金属化合物でも、反応条件を適切に制御することで良質の金属窒化物膜を成膜できるのは言うまでもない。 According to one embodiment of the present invention, an organic metal containing a metal such as a transition metal, which is liquid at normal temperature and pressure and has a high vapor pressure, is used as the raw material. In order to synthesize transition metal nitride, the organometallic raw material is preferably an organometallic molecule in which oxygen that easily forms a chemical bond with the metal element does not exist in the molecule, and a nitrogen atom is coordinated around the transition metal ion. Organometallic molecules are preferred. Of course, it is needless to say that a high-quality metal nitride film can be formed even by using an organometallic compound that does not contain nitrogen by appropriately controlling the reaction conditions.
図１に示される、有機金属を原料として使用したＭＢＥを行うことができるＭＢＥ装置の概念図を用いてさらに詳しく説明すれば、この有機金属原料の液体が入ったステンレス製のボトルである有機金属原料ボトル１２を、図１の右下領域に示すところの専用に開発した真空ガスラインに接続する。この専用真空ガスラインと有機金属原料ボトル１２には、有機金属原料の蒸発量を精密にコントロールするための加熱を行うヒーター（図示せず）が取り付けられている。さらに、この専用真空ガスラインには、気化した有機金属ガスの流量を高精度で制御するための流量コントロールバルブ１１と真空計(流量計)１０が取り付けられている。気化した有機金属原料は、この専用真空ガスラインを通り、新規な構造を有するガスソースセル８を通り、薄膜を形成する真空槽（ＭＢＥ本体成長室１）内へと供給される。 If it demonstrates in more detail using the conceptual diagram of the MBE apparatus which can perform MBE using an organic metal as a raw material shown in FIG. 1, the organic metal which is a stainless steel bottle containing the liquid of this organic metal raw material The raw material bottle 12 is connected to a specially developed vacuum gas line shown in the lower right area of FIG. The dedicated vacuum gas line and the organic metal raw material bottle 12 are provided with a heater (not shown) for heating to precisely control the evaporation amount of the organic metal raw material. Furthermore, a flow rate control valve 11 and a vacuum gauge (flow meter) 10 for controlling the flow rate of the vaporized organometallic gas with high accuracy are attached to the dedicated vacuum gas line. The vaporized organometallic raw material passes through this dedicated vacuum gas line, through the gas source cell 8 having a novel structure, and is supplied into the vacuum chamber (MBE main body growth chamber 1) for forming a thin film.
ガスソースセル８は、その表面に薄膜が形成・成長される基板４とガスソースセル８との間の距離を変えることができる一軸直線移動機構（Ｚステージ）を備えており、基板上での有機金属原料分子の吸着量の制御が可能となっている。両者間の距離を変化させる必要があるのは、ＭＢＥを行う際、その原料の基板表面への吸着のしやすさが原料により異なり、本発明で使用される有機金属は従来使用されてきた原料に比べて吸着しにくいため、従来の両者間の距離が固定されたガスソースセルを使用したＭＢＥ装置は本発明で使用する有機金属原料と適合しないためである。本発明に基づいてＭＢＥを行う装置においても、従来の原料を使用したＭＢＥを行うこともできることが通常は必要となるため、使用原料により変化するガスソースセル８と基板４との間の最適な距離に適合するようにこの距離を所要値に設定できるように可変にしておくことが望ましい。具体的には、従来の原料に比べて吸着しにくい有機金属原料を供給する際にはガスソースセル８と基板４との距離を短くする。 The gas source cell 8 includes a uniaxial linear movement mechanism (Z stage) that can change the distance between the substrate 4 on which the thin film is formed and grown and the gas source cell 8. It is possible to control the amount of organic metal source molecules adsorbed. It is necessary to change the distance between the two when the MBE is performed, the ease of adsorption of the raw material on the substrate surface differs depending on the raw material, and the organic metal used in the present invention is a raw material conventionally used This is because the conventional MBE apparatus using the gas source cell in which the distance between the two is fixed is not compatible with the organometallic raw material used in the present invention. In an apparatus for performing MBE based on the present invention, it is usually necessary to be able to perform MBE using a conventional raw material, so that the optimum between the gas source cell 8 and the substrate 4 that varies depending on the used raw material is required. It is desirable to make this distance variable so that it can be set to a required value so as to match the distance. Specifically, the distance between the gas source cell 8 and the substrate 4 is shortened when supplying an organometallic raw material that is difficult to adsorb as compared with the conventional raw material.
この距離について更に説明すれば、吸着しにくい分子を吸着させるためには、分子の吸着確率を上げるために原料供給源を近づけるか、あるいは原料供給量を増やす必要がある。原料供給量を増やすと圧力が上がり(真空度が低くなる)、反射高速電子線回折（ＲＨＥＥＤ）の使用に影響が出たり、原料供給量の増加による真空度の低下を防ぐために排気量の大きな真空ポンプが必要になったりするという問題が生じる。一方、原料の供給量は原料供給源と基板間距離に反比例するので、原料供給源を基板に近づけるのは有効な手法である。しかし、本発明を従来のＭＢＥ装置に適用して、従来の原料とそのような原料と比べて吸着しにくい有機金属原料とを切り替えて使用することを考えると、多くの装置の場合、原料供給源と基板間距離を変化させる機構を取り付けるためには装置の大がかりな改造が必要となる。もちろん、既存のＭＢＥ装置を有機金属原料専用の装置として使用することを企図したとしても、上記距離が有機金属原料を使用するには大きすぎるので、既存装置をそのまま本発明に使用するのは現実には困難である。そこで、本発明の装置ではガスソースセルと基板との間の距離を可変にできる一軸直線移動機構（Ｚステージ）を備えるようにするのが好ましい。この一軸直線移動機構（Ｚステージ）は、例えばガスソースセルの分子ビーム吹き出し口をその吹き出し方向に沿って前後に移動させる。分子ビーム吹き出し口と基板との間の距離は、吹き出される分子の種類やそのほかのパラメータに合わせて適宜調節する To further explain this distance, in order to adsorb molecules that are difficult to adsorb, it is necessary to bring the raw material supply source closer or increase the raw material supply amount in order to increase the probability of molecular adsorption. Increasing the feed rate increases the pressure (lowering the vacuum level) and affects the use of reflection high-energy electron diffraction (RHEED), or increases the amount of exhaust to prevent a decrease in the vacuum level due to an increase in feed rate. The problem that a vacuum pump becomes necessary arises. On the other hand, since the supply amount of the raw material is inversely proportional to the distance between the raw material supply source and the substrate, it is an effective technique to bring the raw material supply source closer to the substrate. However, considering that the present invention is applied to a conventional MBE apparatus and switching between a conventional raw material and an organometallic raw material that is difficult to adsorb as compared with such a raw material, in many apparatuses, the raw material supply In order to install a mechanism for changing the distance between the source and the substrate, a large-scale modification of the apparatus is required. Of course, even if it is intended to use an existing MBE device as a device dedicated to an organic metal raw material, the distance is too large to use the organic metal raw material, so it is a reality to use the existing device as it is in the present invention. It is difficult. Therefore, the apparatus of the present invention is preferably provided with a uniaxial linear movement mechanism (Z stage) that can vary the distance between the gas source cell and the substrate. This uniaxial linear movement mechanism (Z stage) moves, for example, the molecular beam blowing port of the gas source cell back and forth along the blowing direction. The distance between the molecular beam outlet and the substrate is appropriately adjusted according to the type of molecules to be blown out and other parameters.
ＭＢＥを行うに当たっては、基板４は基板ホルダー３を介して基板加熱機構２により加熱され、使用される特定の有機金属原料及びその他の条件により定まる適切な温度まで昇温される。 In performing MBE, the substrate 4 is heated by the substrate heating mechanism 2 through the substrate holder 3 and heated to an appropriate temperature determined by the specific organometallic raw material used and other conditions.
このＭＢＥ装置には、原子状窒素供給装置（ＲＦプラズマソース）が設けられ、窒素ガスをプラズマ化することで発生した原子状窒素をＭＢＥ本体成長室１内へ供給する。基板４上に吸着された有機金属原料は、加熱により昇温された基板４表面で分解し、供給された原子状窒素と反応することにより、そこに遷移金属窒化物の薄膜を形成する。 This MBE apparatus is provided with an atomic nitrogen supply apparatus (RF plasma source), and supplies atomic nitrogen generated by converting nitrogen gas into plasma into the MBE main body growth chamber 1. The organometallic raw material adsorbed on the substrate 4 is decomposed on the surface of the substrate 4 heated by heating, and reacts with the supplied atomic nitrogen to form a transition metal nitride thin film there.
なお、図１に示した構造ではＭＢＥの原料として遷移金属（有機金属）と窒素のみが供給されるようになっていて、遷移金属窒化物の薄膜を基板上に形成するようになっている。しかし、本発明はこれに限定されるものではなく、多成分系遷移金属窒化物（例えば、ＡＭＮ２、Ａ２ＭＮ２、ＡＭ２Ｎ２等の多様な組成比を有する２種類以上の異なる典型元素の金属または遷移金属を含む窒化物；ここでＭとＡは何れも遷移金属あるいは典型元素の金属である）の薄膜を形成することもできる。これを実現するためには、分子線エピタキシー本体成長室１内に別途設けられた原料供給セル（図示せず）からＡサイトの原子またはその化合物のビームをＭサイト用の有機金属原料の供給と同時に基板４の表面に供給してそこで反応させることで、そこに所望の多成分系遷移金属窒化物の薄膜を形成することができる。 In the structure shown in FIG. 1, only transition metal (organic metal) and nitrogen are supplied as MBE raw materials, and a thin film of transition metal nitride is formed on the substrate. However, the present invention is not limited to this, and multi-component transition metal nitrides (for example, AMN 2 , A 2 MN 2 , AM 2 N 2, etc., two or more different typicals having various composition ratios). It is also possible to form a thin film of an elemental metal or a nitride containing a transition metal, where M and A are both transition metals or typical elemental metals. In order to realize this, a beam of A-site atoms or a compound thereof is supplied from a source supply cell (not shown) separately provided in the molecular beam epitaxy main body growth chamber 1 to supply an M-site organometallic source. At the same time, a desired multicomponent transition metal nitride thin film can be formed on the surface of the substrate 4 by reacting therewith.
図１には、更に反射高速電子線回折用電子銃５及び反射高速電子線回折用スクリーン６も図示されている。これによりこのＭＢＥ装置により作製されている薄膜の反射高速電子線回折像を撮影して、薄膜表面の平坦性や結晶性等の評価を行うことができる。また、通常のＭＢＥ装置に設けることができるその他の装置であれば、本発明にとって有害でない限り適宜選択して採用することができることに注意されたい。 FIG. 1 also shows a reflection high-energy electron diffraction electron gun 5 and a reflection high-energy electron diffraction screen 6. Thereby, the reflection high-energy electron diffraction image of the thin film produced by this MBE apparatus can be image | photographed, and the flatness of a thin film surface, crystallinity, etc. can be evaluated. It should be noted that any other device that can be provided in a normal MBE device can be appropriately selected and employed as long as it is not harmful to the present invention.
本発明は多くの遷移金属に対して適用可能であるが、以下ではその体表的な例としてチタン（Ｔｉ）を例に挙げて説明する。Ｔｉを例として説明しても一般性を失うものでないことは明らかである。 The present invention can be applied to many transition metals. Hereinafter, titanium (Ti) will be described as an example of the body surface. It is clear that even if Ti is taken as an example, generality is not lost.
ここで、本発明において有機金属原料として使用可能な物質の非限定的な例を以下に示す：
・Tetrakis dimethylamino titanium（ＴＤＭＡＴ，Ｔｉ［Ｎ（ＣＨ３）２］４）
Here, non-limiting examples of substances that can be used as organometallic raw materials in the present invention are shown below:
・ Tetrakis dimethylamino titanium (TDMAT, Ti [N (CH 3 ) 2 ] 4 )
・Tetrakisdiethylaminotitanium（ＴＤＥＡＴ，Ｔｉ［Ｎ（Ｃ２Ｈ５）２］４） Tetrakisdiethylaminotitanium (TDEAT, Ti [N (C 2 H 5 ) 2 ] 4 )
・Tetrakisethylmethylaminotitanium（ＴＥＭＡＴ，Ｔｉ［Ｎ（Ｃ２Ｈ５）ＣＨ３］４） Tetrakisethylmethylaminotitanium (TEMAT, Ti [N (C 2 H 5 ) CH 3 ] 4 )
上に例示した３種類の有機金属の物性等を下表に示す。 The physical properties of the three types of organic metals exemplified above are shown in the table below.
Ｔｉ以外の有機金属原料を、もちろんこれらに限定する意図はなく、またこれら以外には存在しないというものでもないが、以下に列挙して例示する。例として取り上げるべき有機化合物を選択するにあたって、購入可能なもので、かつ実際に本願発明者が作成した本発明のＭＢＥ装置で使用可能である、室温（２５℃）近傍で液体のものを候補とし、それらのうちから選択した。したがって、固体（粉末・結晶）の有機金属原料は除外した。もちろん、昇温して気化したうえで有機金属ガスソースセルへ供給するなどの、有機金属の供給系の構造や制御を適宜修正することで、固体等の有機金属でも使用できるようになることは言うまでもない。また、Ｍｇ、Ａｌ等の遷移金属以外の金属の有機化合物も以下に例示した有機金属化合物のリストに含まれる。ここで、通常のＭＢＥでは供給できない、Ｚｒ（ジルコニウム）、Ｔａ（タンタル）、Ｎｂ（ニオブ）、Ｈｆ（ハフニウム）、Ｗ（タングステン）等の原料も存在することに注意されたい。 Of course, the organometallic raw materials other than Ti are not intended to be limited to these, and are not limited to these, but are listed and exemplified below. In selecting an organic compound to be taken up as an example, a candidate is a liquid that is commercially available and can be used in the MBE apparatus of the present invention created by the present inventor and is in the vicinity of room temperature (25 ° C.). Selected from among them. Therefore, solid (powder / crystal) organometallic raw materials were excluded. Of course, it is possible to use organic metals such as solids by appropriately modifying the structure and control of the organic metal supply system, such as raising the temperature and vaporizing and then supplying it to the organic metal gas source cell. Needless to say. Further, organic compounds of metals other than transition metals such as Mg and Al are also included in the list of organometallic compounds exemplified below. Here, it should be noted that there are also raw materials such as Zr (zirconium), Ta (tantalum), Nb (niobium), Hf (hafnium), W (tungsten) which cannot be supplied by ordinary MBE.
・Ｍｇ（マグネシウム）の有機金属化合物の例：
(1) Bis(ethylcyclopentadienyl)magnesium,（Ｃ２Ｈ５Ｃ５Ｈ４）２Ｍｇ
(2) Bis(n-propylcyclopentadienyl)magnesium,（Ｃ３Ｈ７Ｃ５Ｈ４）２Ｍｇ
・Ａｌ（アルミニウム）の有機金属化合物の例：
(3) Tri-i-butylaluminum,（Ｃ４Ｈ９）３Ａｌ
(4) Triethylaluminum,（Ｃ２Ｈ５）３Ａｌ
(5) Trimethylaluminum,（ＣＨ３）３Ａｌ
・Ｖ（バナジウム）の有機金属化合物の例：
(6) Tetrakis(diethylamino)vanadium(IV), ＴＤＥＡＶ，Ｖ［Ｎ（ＣＨ２ＣＨ３）２］４
・Ｃｒ（クロム）の有機金属化合物の例：
(7) Bis(ethylbenzene)chromium,［（Ｃ２Ｈ５）ｘＣ６Ｈ６−ｘ］２Ｃｒ
(8) Bis(i-propylcyclopentadienyl)chromium,［（Ｃ３Ｈ７）Ｃ５Ｈ４］２Ｃｒ
・Ｚｎ（亜鉛）の有機金属化合物の例：
(9) Diethylzinc, Ｚｎ（Ｃ２Ｈ５）２
(10) Dimethylzinc, Ｚｎ（ＣＨ３）２
・Ｇａ（ガリウム）の有機金属化合物の例：
(11)Triethylgallium, （Ｃ２Ｈ５）３Ｇａ
・Ｙ（イットリウム）の有機金属化合物の例：
(12) Tris(butylcyclopentadienyl)yttrium,（Ｃ４Ｈ９Ｃ５Ｈ４）３Ｙ
・Ｚｒ（ジルコニウム）の有機金属化合物の例：
(13)Tetrakis(diethylamino)zirconium, Ｚｒ［Ｎ（ＣＨ２ＣＨ３）２］４
・Ｎｂ（ニオブ）の有機金属化合物の例：
(14)Tris(ethylmethylamido)(tert-butylimido)niobium(V), ＴＢＴＥＭＮ，［（Ｃ２Ｈ５）（ＣＨ３）Ｎ］３Ｎｂ＝Ｎ［Ｃ（ＣＨ３）３］
(15)Tris(diethylamido)(tert-butylimido)niobium(V), ＴＢＴＤＥＮ，［（Ｃ２Ｈ５）２Ｎ］３Ｎｂ＝Ｎ［Ｃ（ＣＨ３）３］
・Ｍｏ（モリブデン）の有機金属化合物の例：
(16)Bis(t-butylimido)bis(dimethylamino) molybdenum(VI), Ｃ１２Ｈ３０ＭｏＮ４
・Ｒｕ（ルテニウム）の有機金属化合物の例：
(17)Bis(ethylcyclopentadienyl)ruthenium(II), ［（ＣＨ３ＣＨ２）Ｃ５Ｈ４］２Ｒｕ
・Ｃｄ（カドミウム）の有機金属化合物の例：
(18) Dimethylcadmium,（ＣＨ３）２Ｃｄ
・Ｓｎ（スズ）の有機化合物の例：
(19) Tetramethyltin,（ＣＨ３）４Ｓｎ
(20) Tetraethyltin,（ＣＨ３ＣＨ２）４Ｓｎ
・Ｈｆ（ハフニウム）の有機金属化合物の例：
(21) Tetrakis(diethylamino)hafnium, Ｈｆ［Ｎ（ＣＨ２ＣＨ３）２］４
(22)Tetrakis(ethylmethylamino)hafnium, Ｈｆ［Ｎ（ＣＨ３）（ＣＨ２ＣＨ３）］４
・Ｔａ（タンタル）の有機金属化合物の例：
(23)(t-Butylimido)tris(diethylamino)tantalum(V), Ｃ１６Ｈ３９Ｎ４Ｔａ
・Ｗ（タングステン）の有機金属化合物の例：
(24) Bis(t-butylimido)bis(dimethylamido) tungsten(VI), Ｃ１２Ｈ３０Ｎ４Ｗ
・Ｉｒ（イリジウム）の有機金属化合物の例：
(25)1-Ethylcyclopentadienyl-1,3-cyclohexadieneiridium(I), Ｃ１３Ｈ１７Ｉｒ
・Ｌａ（ランタン）の有機金属化合物の例：
(26) Tris(i-propylcyclopentadienyl)lanthanum,（Ｃ３Ｈ７Ｃ５Ｈ４）３Ｌａ
・Ｅｒ（エルビウム）の有機金属化合物の例：
(27) Tris(n-butylcyclopentadienyl)erbium,（Ｃ４Ｈ９Ｃ５Ｈ４）３Ｅｒ
-Examples of organometallic compounds of Mg (magnesium):
(1) Bis (ethylcyclopentadienyl) magnesium, (C 2 H 5 C 5 H 4 ) 2 Mg
(2) Bis (n-propylcyclopentadienyl) magnesium, (C 3 H 7 C 5 H 4 ) 2 Mg
-Examples of organometallic compounds of Al (aluminum):
(3) Tri-i-butylaluminum , (C 4 H 9) 3 Al
(4) Triethylaluminum, (C 2 H 5 ) 3 Al
(5) Trimethylaluminum, (CH 3 ) 3 Al
Examples of organometallic compounds of V (vanadium):
(6) Tetrakis (diethylamino) vanadium (IV), TDEAV, V [N (CH 2 CH 3 ) 2 ] 4
Examples of organometallic compounds of Cr (chromium):
(7) Bis (ethylbenzene) chromium, [(C 2 H 5 ) x C 6 H 6-x ] 2 Cr
(8) Bis (i-propylcyclopentadienyl) chromium, [(C 3 H 7 ) C 5 H 4 ] 2 Cr
-Examples of organometallic compounds of Zn (zinc):
(9) Diethylzinc, Zn (C 2 H 5 ) 2
(10) Dimethylzinc, Zn (CH 3 ) 2
Examples of organometallic compounds of Ga (gallium):
(11) Triethylgallium, (C 2 H 5 ) 3 Ga
-Examples of organometallic compounds of Y (yttrium):
(12) Tris (butylcyclopentadienyl) yttrium, (C 4 H 9 C 5 H 4 ) 3 Y
Examples of organometallic compounds of Zr (zirconium):
(13) Tetrakis (diethylamino) zirconium, Zr [N (CH 2 CH 3 ) 2 ] 4
Examples of organometallic compounds of Nb (niobium):
(14) Tris (ethylmethylamido) (tert-butylimido) niobium (V), TBTEMN, [(C 2 H 5 ) (CH 3 ) N] 3 Nb = N [C (CH 3 ) 3 ]
(15) Tris (diethylamido) (tert-butylimido) niobium (V), TBTDEN, [(C 2 H 5 ) 2 N] 3 Nb = N [C (CH 3 ) 3 ]
-Examples of organometallic compounds of Mo (molybdenum):
(16) Bis (t-butylimido) bis (dimethylamino) molybdenum (VI), C 12 H 30 MoN 4
-Examples of organometallic compounds of Ru (ruthenium):
(17) Bis (ethylcyclopentadienyl) ruthenium (II), [(CH 3 CH 2 ) C 5 H 4 ] 2 Ru
Examples of organometallic compounds of Cd (cadmium):
(18) Dimethylcadmium, (CH 3 ) 2 Cd
-Examples of organic compounds of Sn (tin):
(19) Tetramethyltin, (CH 3 ) 4 Sn
(20) Tetraethyltin, (CH 3 CH 2 ) 4 Sn
-Examples of organometallic compounds of Hf (hafnium):
(21) Tetrakis (diethylamino) hafnium, Hf [N (CH 2 CH 3 ) 2 ] 4
(22) Tetrakis (ethylmethylamino) hafnium, Hf [N (CH 3 ) (CH 2 CH 3 )] 4
Examples of organometallic compounds of Ta (tantalum):
(23) (t-Butylimido) tris (diethylamino) tantalum (V), C 16 H 39 N 4 Ta
-Examples of organometallic compounds of W (tungsten):
(24) Bis (t-butylimido) bis (dimethylamido) tungsten (VI), C 12 H 30 N 4 W
Examples of organometallic compounds of Ir (Iridium):
(25) 1-Ethylcyclopentadienyl-1,3-cyclohexadieneiridium (I), C 13 H 17 Ir
Examples of organometallic compounds of La (lanthanum):
(26) Tris (i-propylcyclopentadienyl) lanthanum, (C 3 H 7 C 5 H 4 ) 3 La
-Examples of organometallic compounds of Er (erbium):
(27) Tris (n-butylcyclopentadienyl) erbium, (C 4 H 9 C 5 H 4 ) 3 Er
＜実施例：有機金属原料としてＴＤＭＡＴを用いた窒化チタン（ＴｉＮ）エピタキシャル薄膜の作製＞
図１に構成例を示す、有機金属原料供給システムを備えたＭＢＥを用いて、高品質窒化チタン（ＴｉＮ）エピタキシャル薄膜を作製した。遷移金属であるチタン（Ｔｉ）の有機金属原料としてＴＤＭＡＴを用いた。このＴＤＭＡＴの分子構造はＴｉの周りに４つの窒素が配位した構造であるため、内包する窒素原子が窒化チタン薄膜成長へ寄与することが期待される。
<Example: Production of titanium nitride (TiN) epitaxial thin film using TDMAT as organic metal raw material>
A high-quality titanium nitride (TiN) epitaxial thin film was produced using MBE equipped with an organometallic raw material supply system as shown in FIG. TDMAT was used as an organometallic raw material for titanium (Ti), which is a transition metal. Since the molecular structure of TDMAT is a structure in which four nitrogens are coordinated around Ti, it is expected that the nitrogen atoms contained will contribute to the growth of the titanium nitride thin film.
図１に示すように、有機金属供給システムに接続されたＴＤＭＡＴ原料ボトル１２を加熱し、気化させ、加熱されたガスラインを経て、薄膜を成長する真空槽１内へＴＤＭＡＴを供給した。図２に示すように、ここで使用したＴＤＭＡＴ等の常温で液体である各種の有機金属は、従来使用されまた使用が検討されてきたＳｒ、Ｓｎ、Ｓｉ、Ｔｉ等の固体状態の金属原料に比べ、非常に低い温度で気化し、極めて高い蒸気圧を有する。また、固体の有機金属原料は、液体の有機金属原料ほどではないにせよ、Ｓｒ、Ｓｎ、Ｓｉ、Ｔｉ等の固体原料に比べて融点は低く蒸気圧は高い。したがって、液体の有機金属だけでなく常温で固体の有機金属も本発明の金属材料として使用することができる。これにより、有機金属は金属化合物の成膜のためにＭＢＥで使用する金属原料として非常に好適である。このガスラインには、ＴＤＭＡＴガスの圧力を高精度で測定し、流量を調整することができる真空計１０及び流量コントロールバルブ１１が備わっている。真空槽１内に設けられたガスソースセル８を介して、真空槽１内に設置され、その表面に薄膜を形成すべき基板４へ向けてＴＤＡＭＴの分子ビームを供給した。ガスソースセル８は分子ビーム吹き出し方向に沿って、吹き出し口を前後に移動できる一軸直線移動機構（Ｚステージ）を備えており、ビーム吹き出し口と基板４との距離を必要な薄膜成長速度に合わせて設定できるようになっている。基板４として、チタン酸ストロンチウム単結晶の基板（ＳｒＴｉＯ３（１００））を使用し、これを基板加熱機構２により６００℃〜９００℃に加熱した。Ｔｉ原料であるＴＤＭＡＴの供給と同時に、窒素（Ｎ）の原料として高周波（Radio Frequency，ＲＦ）プラズマソース７から発生する原子状窒素の供給も行った。ここで、上で説明したように、ビーム吹き出し口と基板４との距離を最適化して成膜を行った。これにより、基板４表面にＴｉＮエピタキシャル薄膜を形成した。 As shown in FIG. 1, the TDMAT raw material bottle 12 connected to the organometallic supply system was heated and vaporized, and TDMAT was supplied into the vacuum chamber 1 in which a thin film was grown through the heated gas line. As shown in FIG. 2, various organic metals that are liquid at room temperature, such as TDMAT used here, are used as solid-state metal raw materials such as Sr, Sn, Si, and Ti that have been used and studied. In comparison, it vaporizes at a very low temperature and has a very high vapor pressure. Moreover, the solid organometallic raw material has a lower melting point and higher vapor pressure than solid raw materials such as Sr, Sn, Si, and Ti, though not as much as a liquid organometallic raw material. Therefore, not only a liquid organic metal but also an organic metal that is solid at room temperature can be used as the metal material of the present invention. Thereby, the organic metal is very suitable as a metal raw material used in MBE for forming a metal compound. This gas line includes a vacuum gauge 10 and a flow rate control valve 11 that can measure the pressure of the TDMAT gas with high accuracy and adjust the flow rate. A TDAMT molecular beam was supplied through a gas source cell 8 provided in the vacuum chamber 1 toward the substrate 4 on which the thin film was to be formed. The gas source cell 8 is equipped with a uniaxial linear movement mechanism (Z stage) that can move the blowing port back and forth along the molecular beam blowing direction, and adjusts the distance between the beam blowing port and the substrate 4 to the required thin film growth rate. Can be set. As the substrate 4, a strontium titanate single crystal substrate (SrTiO 3 (100)) was used and heated to 600 ° C. to 900 ° C. by the substrate heating mechanism 2. Simultaneously with the supply of TDMAT, which is a Ti raw material, atomic nitrogen generated from a radio frequency (RF) plasma source 7 was also supplied as a raw material for nitrogen (N). Here, as described above, the film was formed by optimizing the distance between the beam outlet and the substrate 4. Thereby, a TiN epitaxial thin film was formed on the surface of the substrate 4.
図３に示すように、高い表面平坦性と高結晶、さらにエピタキシャル成長を意味するストリーク状の反射高速電子線回折像が、基板４の表面に作製中の薄膜から得られた。 As shown in FIG. 3, a streak-like reflection high-energy electron diffraction image indicating high surface flatness, high crystal, and epitaxial growth was obtained from the thin film being formed on the surface of the substrate 4.
作製したＴｉＮエピタキシャル薄膜のＸ線回折パターンを測定し、図４に示されるパターンを得た。これらのＸ線回折パターンでは、基板であるＳｒＴｉＯ３と岩塩型結晶構造のＴｉＮの回折ピークのみが観測され、異相を含まない単相の試料が得られていることが示された。ＴｉＮ薄膜のピーク強度は非常に大きく、高角度側のＴｉＮ（４００）回折ピークにおいても、ＣｕＫ １線とＣｕＫ ２線による回折ピークの明瞭な分離が確認され、高い結晶性を有することが明らかになった。また、作製したＴｉＮ薄膜の格子定数（０．４２４６ｎｍ）がバルクの格子定数（０．４２４１７３ｎｍ，ＩＣＤＤ＃００−０３８−１４２０）とほぼ一致することから、ストイキオメトリーな薄膜が得られていることが分かった。 The X-ray diffraction pattern of the produced TiN epitaxial thin film was measured, and the pattern shown in FIG. 4 was obtained. In these X-ray diffraction patterns, only the diffraction peaks of SrTiO 3 as a substrate and TiN having a rock salt type crystal structure were observed, indicating that a single-phase sample containing no heterogeneous phase was obtained. The peak intensity of the TiN thin film is very large, and even in the TiN (400) diffraction peak on the high angle side, clear separation of the diffraction peaks by the CuK 1 line and the CuK 2 line is confirmed, and it is clear that the TiN thin film has high crystallinity. became. Further, since the lattice constant (0.4246 nm) of the manufactured TiN thin film substantially matches the bulk lattice constant (0.424173 nm, ICDD # 00-038-1420), a stoichiometric thin film is obtained. I understood.
以上から、本発明によれば、ＭＢＥを行うにあたって遷移金属の供給レートを精密に観測して制御することなしに、非常に高品質の遷移金属窒化物のエピタキシャル薄膜を容易に作製できる。 From the above, according to the present invention, it is possible to easily produce a very high-quality transition metal nitride epitaxial thin film without precisely observing and controlling the transition metal supply rate when performing MBE.
遷移金属を含んだ有機金属を原料として用いる分子線エピタキシー方法、またその装置により、ＥＩＥＳ等の高価な分光装置を利用することなく、遷移金属原料の精度の高い供給量制御と、より広いレンジで原料供給速度を変化させることが可能となった。本発明により、遷移金属窒化物、特に多成分系遷移金属窒化物の良質な試料作製が可能となり、新物質開拓や機能開拓研究の促進が期待される。 With a molecular beam epitaxy method using an organic metal containing a transition metal as a raw material and its apparatus, it is possible to control the supply amount of the transition metal raw material with high accuracy and a wider range without using an expensive spectroscopic device such as EIES. It became possible to change the raw material supply speed. The present invention enables preparation of high-quality samples of transition metal nitrides, particularly multi-component transition metal nitrides, and is expected to promote new material development and functional development research.
１：分子線エピタキシー本体成長室
２：基板加熱機構
３：基板ホルダー
４：基板
５：反射高速電子線回折用電子銃
６：反射高速電子線回折用スクリーン
７：原子状窒素供給装置（ＲＦプラズマソース）
８：有機金属ガスソースセル
９：有機金属原料供給システム
１０：真空計
１１：流量コントロールバルブ
１２：有機金属原料ボトル
1: Molecular beam epitaxy main body growth chamber 2: Substrate heating mechanism 3: Substrate holder 4: Substrate 5: Electron gun for reflection high-energy electron diffraction 6: Screen for reflection high-energy electron diffraction 7: Atomic nitrogen supply device (RF plasma source) )
8: Organometallic gas source cell 9: Organometallic raw material supply system 10: Vacuum gauge 11: Flow rate control valve 12: Organometallic raw material bottle
Claims (17)
内部で前記成膜が行われる真空槽と、
気化された有機金属を供給する有機金属供給部と、
前記有機金属供給部から供給された前記有機金属の気体を前記真空槽内に置かれた前記基板に供給するガスソースセルと
を設けた、分子線エピタキシー装置。 A molecular beam epitaxy apparatus for depositing a metal compound on a substrate by molecular beam epitaxy,
A vacuum chamber in which the film formation is performed;
An organic metal supply unit for supplying vaporized organic metal;
A molecular beam epitaxy apparatus provided with a gas source cell for supplying the organic metal gas supplied from the organic metal supply unit to the substrate placed in the vacuum chamber.
前記基板へ前記原料が吸着されにくい程、前記基板と前記ガスソースセルとの間の距離を小さくするように設定できる
請求項１３に記載の分子線エピタキシー装置。 As a raw material for molecular beam epitaxy, the organic metal and a substance other than the organic metal are selectively supplied from the gas source cell to the substrate,
The molecular beam epitaxy apparatus according to claim 13, wherein the distance between the substrate and the gas source cell can be set to be smaller as the raw material is less likely to be adsorbed to the substrate.
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