JPH0587747A - X-ray diffraction method for thin film in energy dispersion type total reflection surface - Google Patents
X-ray diffraction method for thin film in energy dispersion type total reflection surfaceInfo
- Publication number
- JPH0587747A JPH0587747A JP3274835A JP27483591A JPH0587747A JP H0587747 A JPH0587747 A JP H0587747A JP 3274835 A JP3274835 A JP 3274835A JP 27483591 A JP27483591 A JP 27483591A JP H0587747 A JPH0587747 A JP H0587747A
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- Prior art keywords
- rays
- thin film
- substrate
- slit
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Abstract
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、白色Ｘ線を利用して薄
膜の面内結晶構造、高次構造の評価を行うＸ線回折法に
関する。
【０００２】
【従来の技術】最も一般的な回折法は、単色Ｘ線を利用
するもので、試料に対するＸ線の入射角をθとすると、
試料を角度θで、Ｘ線検出器を角度２θで回転させて、
回折ピークを測定する、いわゆるθー２θ走査法であ
る。 しかし、この方法で基板上の薄膜を測定すると、
薄膜下の基板からの散乱が強く、相対的に薄膜からの回
折強度が弱くなり、Ｓ／Ｎ比が小さくなつてしまう。そ
こで、多結晶薄膜試料に対しては試料に対するＸ線の入
射角を低入射角（たとえば２゜〜３゜）に固定して、Ｘ
線検出器だけを２θ回転する方法が知られている（この
方法では、試料台に薄膜アタッチメントを設ける）。こ
のようにすれば、Ｘ線の薄膜通過距離を長くすることが
出来て、薄膜からの回折強度を大きくすることができ
る。これらの方法はいずれも多結晶試料を用いる粉末法
であり、単結晶や高度に配向した薄膜試料（Ｌ．Ｂ膜
等）の構造評価は原理的に不可能であつた。
【０００３】
【発明が解決しようとする課題】
（１）[０００２]の薄膜アタッチメント法においても、
薄膜が薄くなればなるほど、相対的に基板からの散乱の
影響が大きくなり、鮮明な回折プロファイルを得るのは
困難になって来る。最近、Ｌ．Ｂ膜で代表されるよう
に、原子、分子が高度に配列制御された超薄膜の構造評
価技術が強く求められている現状から、本課題の解決が
望まれる。
（２）[０００２]の薄膜アタッチメント法は原理的に単
結晶や高度に配向した分子性結晶薄膜の評価には用いら
れない。特に、薄膜面内の凝集構造の評価法の開発は緊
急の課題である。
（３）産業上有用な機能性薄膜の創製法の一つに真空蒸
着法や分子線エピタキシー（ＭＢＥ）法等の乾式法があ
る。この方法は基板温度や蒸着速度等のパラメータを変
化させて結晶構造や高次構造を制御出来るが、そのため
には、成長中の薄膜の構造の”その場”での観察が必要
となる。この”その場”解析に当たっては真空槽内に分
析装置を設置しなければならず、装置としてはなるべく
可動部分のないものが望ましい。そこで、上述の[００
０２]の薄膜アタッチメント法はＸ線検出器を回転させ
なければならず、”その場”解析には向いていない。
本発明は、このような事情に鑑みてなされたものであ
り、その目的は上述の課題（１）、（３）の解決は基よ
り、特に、（２）の面内凝集構造の評価法の開発にあ
る。
【０００４】
【課題を解決するための手段】課題（１）の解決はＸ線
の全反射現象を利用しておこなわれる。すなわち、基板
上に形成された薄膜に低角にＸ線を入射させて薄膜と基
板の境界面で全反射させると、基板へのＸ線の侵入深さ
は数ｎｍ程度になり基板からの散乱が著しく減少する。
その結果、薄膜からの回折Ｘ線相対強度（Ｓ／Ｎ比）の
約二桁の改善によって、単分子膜等の超薄膜の構造解析
が可能になる。詳しい説明は関連特許出願（参考文献：
出願番号６３ー８２３５９）を参照されたい。課題
（２）は面内凝集構造の評価法の開発で解決される。
ところで、エネルギー分散方式全反射薄膜Ｘ線回折計は
分光系の幾何学的配置の違いによつて、二つの方式が構
成できる。 図１に、両方式のエヴァルド構成図をＬＢ
膜（分子鎖が基板に対して垂直に配向している）の観測
例として示した。１つは長周期構造（00L反射）観測の
回折条件で、回折ベクトルがKvであり、散乱面は基板面
に垂直になる。従って垂直タイプ全反射薄膜Ｘ線回折法
と名づける。このタイプの逆格子ベクトル（σ00L） は
基板に垂直で、分子の縦方向の構造（スッタキング）が
観測できる（関連特許出願、出願番号６３ー８２３５
９）。。他のシステムは回折ベクトルがKpで、散乱面が
基板面に平行となり、平行タイプ全反射薄膜Ｘ線回折法
とする。このタイプの逆格子ベクトル（σhk0）は基板
に対して平行なので、分子の横方向の構造（サイドパッ
キング）が観測される。さらに、これは視射角φが非常
に小さいため、散乱面が薄膜内に存在するのでIn-Plane
（面内）全反射Ｘ線回折法として本特許出願の発明とし
た。課題（３）の”その場”解析は本手法がエネルギー
分散型回折計のために本質的に可動部がないことによつ
て容易にできる。
【０００５】
【実施例】図２に全反射面内薄膜Ｘ線回折装置の概略図
を示した。 Ｘ線源にはMo（モリブデン）の白色Ｘ線を
用いる。 このために、光学系が固定（２θ：一定）さ
れていても、ブラッグの回折条件を満たす複数の回折Ｘ
線を同時に、しかも、広いＱ（momentum transfer vect
or）にわたって観測することができる。Ｘ線源はライン
フォーカスを用いるので発散角2×10-3deg以下の入射角
設定用ソーラースリット（１２）を用いる。全反射角度
の設定のために入射角設定用スリット（１１）で視射角
φを調節する。 これらの入射スリットシステムは３軸
調整機能を有する。 薄膜からの回折Ｘ線は回折角（２
θ）設定用ソーラースリット（１４）と面内回折線の散
乱Ｘ線制限スリット（１３）で構成されるスリットシス
テムを経てしＳｉ（Ｌｉ）固体Ｘ線検出器ＳＳＤでエネ
ルギー分析される。
【０００６】（実験）図２の概略図に示した水平タイプ
回折法を用いて分子軸（ｃ軸）が基板面に垂直に配向し
た時の温度変化に伴う分子のサイドパッキング（面内凝
集構造）を測定した。 トリトリアコンタン（ｎ−Ｃ33
Ｈ68）を用い、 真空度 1x10-6Torr、 蒸着速度 1A/sec
の条件下で、光学研磨した石英ガラス基板に蒸着し蒸着
膜（膜厚4000A）とそのバルクを試料とした。 基板上
に機械的に配向させたバルク試料の温度変化に伴う200,
110反射回折プロファイルを蒸着膜との比較のため図３
に示した。 斜方晶及び単斜晶から六方晶（回転相）へ
の相転移が同図から良くわかり、転移温度や格子定数値
は文献値と良く一致している。 図４に蒸着薄膜のＸ線
回折プロファイルを示す。バルク試料に較べて明らかに
異なった結晶構造を示していて、蒸着直後の分子の凝集
構造は六方晶で昇温で直接回転相の六方晶へ転移してい
る。さらに、降温２日後の測定では安定な斜方晶に変化
していて蒸着によって、コンフォメ−ション変化を含む
分子間の乱れの導入が示唆される。
【０００７】
【発明の効果】以上説明したように本発明は、薄膜に白
色Ｘ線を低角で入射させ、薄膜と基板との境界面での全
反射効果によるＳ／Ｎ比の著しい改善を達成し、更に、
面内構造の観測が出来る分光系の考案によって実験例で
示したように、分子凝集構造に関する新しい知見がえら
れた。 又、機械的可動部分を必要としないので、真空
中での”その場”観測を容易にする。以上述べたよう
に、本発明による面内構造やエピタキシャル配向のin-s
itu測定は他に手段がなく超薄膜の構造評価に威力を発
揮し、各分野での新材料開発研究の新手法として広く利
用されると考えられる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diffraction method for evaluating the in-plane crystal structure and higher order structure of a thin film by using white X-rays. The most common diffraction method uses monochromatic X-rays, where θ is the angle of incidence of X-rays on a sample.
Rotate the sample at angle θ and the X-ray detector at angle 2θ,
This is a so-called θ-2θ scanning method for measuring a diffraction peak. However, when measuring a thin film on a substrate with this method,
The scattering from the substrate under the thin film is strong, the diffraction intensity from the thin film is relatively weak, and the S / N ratio becomes small. Therefore, for a polycrystalline thin film sample, the incident angle of X-rays on the sample is fixed to a low incident angle (for example, 2 ° to 3 °), and X
A method is known in which only the line detector is rotated 2θ (in this method, a thin film attachment is provided on the sample stage). By doing so, the X-ray passing distance of the thin film can be lengthened and the diffraction intensity from the thin film can be increased. All of these methods are powder methods using a polycrystalline sample, and it has been impossible in principle to evaluate the structure of a single crystal or a highly oriented thin film sample (LB film or the like). (1) Even in the thin film attachment method of [0002],
As the thin film becomes thinner, the influence of scattering from the substrate becomes relatively large, and it becomes difficult to obtain a sharp diffraction profile. Recently, L. The solution of this problem is desired from the current situation that there is a strong demand for a structure evaluation technique for an ultra-thin film in which atoms and molecules are highly array-controlled as represented by the B film. (2) In principle, the thin film attachment method of [0002] cannot be used to evaluate single crystals or highly oriented molecular crystal thin films. In particular, the development of a method for evaluating the in-plane aggregation structure of a thin film is an urgent task. (3) One of the industrially useful functional thin film creation methods is a dry method such as a vacuum deposition method or a molecular beam epitaxy (MBE) method. This method can control the crystal structure and higher-order structure by changing parameters such as substrate temperature and deposition rate, but for that purpose, "in-situ" observation of the structure of the growing thin film is required. In this "in-situ" analysis, an analysis device must be installed in the vacuum chamber, and it is desirable that the device has no moving parts. Therefore, the above [00
02] thin film attachment method requires rotating the X-ray detector and is not suitable for “in-situ” analysis. The present invention has been made in view of the above circumstances, and its object is to solve the problems (1) and (3) described above, and in particular, to (2) the method for evaluating an in-plane aggregate structure. In development. The problem (1) is solved by utilizing the phenomenon of total reflection of X-rays. That is, when X-rays are incident on the thin film formed on the substrate at a low angle and are totally reflected at the boundary surface between the thin film and the substrate, the penetration depth of the X-rays into the substrate is about several nm, and scattering from the substrate occurs. Is significantly reduced.
As a result, the diffraction X-ray relative intensity (S / N ratio) from the thin film is improved by about two orders of magnitude, which enables structural analysis of an ultra-thin film such as a monomolecular film. For detailed explanation, refer to the related patent application (references:
See application number 63-82359). Problem (2) is solved by the development of an evaluation method for the in-plane aggregation structure.
By the way, the energy dispersion type total reflection thin film X-ray diffractometer can be constructed in two ways depending on the difference in the geometrical arrangement of the spectroscopic system. Fig. 1 shows the LB diagram of both types of Ewald.
It is shown as an example of observation of a film (molecular chains are oriented perpendicular to the substrate). One is the diffraction condition for long-period structure (00L reflection) observation, the diffraction vector is Kv, and the scattering surface is perpendicular to the substrate surface. Therefore, it is named vertical type total reflection thin film X-ray diffraction method. This type of reciprocal lattice vector (σ 00L ) is perpendicular to the substrate, and the vertical structure (stacking) of the molecule can be observed (related patent application, application number 63-8235).
9). .. The other system is a parallel type total reflection thin film X-ray diffraction method in which the diffraction vector is Kp and the scattering surface is parallel to the substrate surface. Since this type of reciprocal lattice vector (σ hk0 ) is parallel to the substrate, the lateral structure (side packing) of the molecule is observed. In addition, since the glancing angle φ is very small, the scattering surface exists in the thin film, so the In-Plane
(In-plane) The invention of this patent application was made as a total reflection X-ray diffraction method. The "in-situ" analysis of problem (3) can be facilitated by the fact that this method has essentially no moving parts due to the energy dispersive diffractometer. FIG. 2 shows a schematic view of a total reflection in-plane thin film X-ray diffraction apparatus. A white X-ray of Mo (molybdenum) is used as the X-ray source. For this reason, even if the optical system is fixed (2θ: constant), a plurality of diffraction X satisfying the Bragg diffraction condition is satisfied.
Lines at the same time and wide Q (momentum transfer vect
or)). Since the X-ray source uses a line focus, the incident angle setting solar slit (12) having a divergence angle of 2 × 10 −3 deg or less is used. The glancing angle φ is adjusted by the incident angle setting slit (11) for setting the total reflection angle. These entrance slit systems have a triaxial adjustment function. The diffracted X-ray from the thin film has a diffraction angle (2
Energy is analyzed by a Si (Li) solid-state X-ray detector SSD through a slit system composed of a θ) setting solar slit (14) and a scattered X-ray limiting slit (13) for in-plane diffraction rays. (Experiment) Using the horizontal type diffraction method shown in the schematic view of FIG. 2, side packing of molecules (in-plane agglomeration structure) due to temperature change when the molecular axis (c-axis) is oriented perpendicular to the substrate surface. ) Was measured. Tritriacontane (n-C 33
H 68 ), vacuum degree 1x10 -6 Torr, deposition rate 1A / sec
Under the conditions described above, a vapor-deposited film (film thickness 4000 A) and its bulk were vapor-deposited on a quartz glass substrate that had been optically polished, and used as a sample. 200 with temperature change of bulk sample mechanically oriented on substrate,
Figure 3 shows the 110 reflection diffraction profile for comparison with the deposited film.
It was shown to. The phase transition from orthorhombic and monoclinic to hexagonal (rotating phase) is clearly understood from the figure, and the transition temperature and lattice constant values are in good agreement with the literature values. FIG. 4 shows the X-ray diffraction profile of the deposited thin film. The crystal structure is distinctly different from that of the bulk sample, and the agglomerated structure of the molecules immediately after vapor deposition is hexagonal and is transformed to the hexagonal crystal of the rotational phase directly at elevated temperature. Furthermore, the measurement after 2 days of cooling has changed to a stable orthorhombic crystal, which suggests the introduction of intermolecular disorder including a conformational change due to vapor deposition. As described above, according to the present invention, white X-rays are incident on the thin film at a low angle to significantly improve the S / N ratio due to the total reflection effect at the interface between the thin film and the substrate. Achieved, and
As a result of devising a spectroscopic system capable of observing the in-plane structure, new information on the molecular aggregation structure was obtained as shown in the experimental example. It also facilitates "in-situ" observations in vacuum because it does not require mechanically moving parts. As described above, the in-plane structure of the in-plane structure and the epitaxial orientation according to the present invention
In situ measurement has no other means and is effective for structural evaluation of ultra-thin films, and is considered to be widely used as a new method for research and development of new materials in various fields.
【図面の簡単な説明】
【図１】全反射薄膜Ｘ線回折法のエバルト構成図を示
す。基板に垂直な散乱面（ベクトル：Ｓｖ，Ｋｖ，Ｋｏ
を含む）での回折を垂直法（積層測定）、他を、水平法
（面内構造測定）と定義する。
【図２】エネルギ−分散型全反射面内薄膜Ｘ線回折法の
概略図
【図３】ｎ−アルカン結晶の基板へのＣ軸配向粉末試料
の面内回折法によるＸ線回折プロファイル
【図４】ｎ−アルカン結晶のＣ軸配向蒸着膜試料の面内
回折法によるＸ線回折プロファイル
【符号の説明】
１０ 基板（薄膜）
１１ 全反射設定用スリット
１２ 入射角設定用ソーラスリット
１３ 散乱Ｘ線制限スリット
１４ 回折角設定ソーラスルット
１５ Ｓｉ（Ｌｉ）固体Ｘ線検出器BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an Ewald configuration diagram of a total reflection thin film X-ray diffraction method. Scattering plane perpendicular to the substrate (vector: Sv, Kv, Ko
Is defined as a vertical method (lamination measurement), and others are defined as a horizontal method (in-plane structure measurement). FIG. 2 is a schematic view of an energy-dispersive type total reflection in-plane thin film X-ray diffraction method. FIG. 3 is an X-ray diffraction profile of a C-axis oriented powder sample on a substrate of n-alkane crystal by an in-plane diffraction method. X-ray diffraction profile of C-axis oriented vapor deposition film sample of n-alkane crystal by in-plane diffraction method [Explanation of symbols] 10 substrate (thin film) 11 slit for total reflection setting 12 solar slit for incident angle setting 13 scattering X-ray limitation Slit 14 Diffraction angle setting solar lut 15 Si (Li) solid-state X-ray detector
Claims (1)
線回折法。 （ａ）被測定薄膜が基板上に形成されている試料を準備
する段階。 （ｂ）前期薄膜に白色Ｘ線を基板面に低角に入射して、
薄膜と基板との境界面でＸ線を全反射させる段階。 （ｃ）前記試料表面に対して散乱面（入射、回折、およ
び散乱の各ベクトルを含む面）が平行位置にあり、か
つ、試料との相対位置関係が固定されている固体Ｘ線検
出器で、前記試料からの回折Ｘ線を測定する段階。 （ｄ）前記固体Ｘ線検出器からの出力信号をエネルギ−
分析して、各エネルギ−におけるＸ線強度デ−タから結
晶構造を求める段階。Claims: Energy-dispersive total reflection in-plane thin film X comprising the following steps:
Line diffraction method. (A) Preparing a sample having a thin film to be measured formed on a substrate. (B) Injecting white X-rays into the thin film on the substrate surface at a low angle,
Total reflection of X-rays at the interface between the thin film and the substrate. (C) A solid-state X-ray detector having a scattering surface (a surface including incident, diffraction, and scattering vectors) in parallel to the sample surface and having a fixed relative positional relationship with the sample. Measuring diffracted X-rays from the sample. (D) Energy of the output signal from the solid-state X-ray detector
Analyzing and obtaining a crystal structure from the X-ray intensity data at each energy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3274835A JPH0587747A (en) | 1991-09-25 | 1991-09-25 | X-ray diffraction method for thin film in energy dispersion type total reflection surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3274835A JPH0587747A (en) | 1991-09-25 | 1991-09-25 | X-ray diffraction method for thin film in energy dispersion type total reflection surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0587747A true JPH0587747A (en) | 1993-04-06 |
Family
ID=17547251
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3274835A Pending JPH0587747A (en) | 1991-09-25 | 1991-09-25 | X-ray diffraction method for thin film in energy dispersion type total reflection surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0587747A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5285934A (en) * | 1991-01-14 | 1994-02-15 | Ryobi, Ltd. | Automatic molten metal supplying device |
| EP0578387B1 (en) * | 1992-06-17 | 1998-03-18 | Ryobi Ltd. | Low pressure die-casting machine and low pressure die-casting method |
-
1991
- 1991-09-25 JP JP3274835A patent/JPH0587747A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5285934A (en) * | 1991-01-14 | 1994-02-15 | Ryobi, Ltd. | Automatic molten metal supplying device |
| EP0578387B1 (en) * | 1992-06-17 | 1998-03-18 | Ryobi Ltd. | Low pressure die-casting machine and low pressure die-casting method |
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