JP6369987B2 - Electron source - Google Patents
Electron source Download PDFInfo
- Publication number
- JP6369987B2 JP6369987B2 JP2014244963A JP2014244963A JP6369987B2 JP 6369987 B2 JP6369987 B2 JP 6369987B2 JP 2014244963 A JP2014244963 A JP 2014244963A JP 2014244963 A JP2014244963 A JP 2014244963A JP 6369987 B2 JP6369987 B2 JP 6369987B2
- Authority
- JP
- Japan
- Prior art keywords
- electron source
- tip
- electron
- tip member
- dimensional nanostructure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Description
本発明は電子光学装置に使用される電子源に関し、特に放出される電子線の光軸からの偏倚を防止した電子源に関する。 The present invention relates to an electron source used in an electron optical device, and more particularly to an electron source that prevents deviation of an emitted electron beam from an optical axis.
走査電子顕微鏡、透過電子顕微鏡、電子ビームリソグラフィー装置等の電子光学装置は皆、分解能を高くしたり、小さなプローブサイズで大きなプローブ電流を得るために、高輝度電子源を必要としている。冷陰極電界放出型電子源は全ての電子源中で最大の輝度を有する。 Electron optical devices such as scanning electron microscopes, transmission electron microscopes, and electron beam lithography devices all require a high-brightness electron source in order to increase resolution or obtain a large probe current with a small probe size. The cold cathode field emission electron source has the maximum brightness among all the electron sources.
従来の冷陰極電界放出型電子源は（３１０）方位の単結晶タングステン針で作成されていた。しかしタングステン表面の反応性が高いという性質により、このような電子放出源は電子銃チャンバー内の残留ガスによる汚染を受けがちであった。その結果、その放出電流には、表面クリーニング直後から急激な減少が見られた。典型的な例として、真空度１０−９ｔｏｒｒでは、電流は２０分以内に初期値の１０％未満まで低下していた。 Conventional cold cathode field emission electron sources have been made with single crystal tungsten needles of (310) orientation. However, due to the high reactivity of the tungsten surface, such an electron emission source tends to be contaminated by residual gas in the electron gun chamber. As a result, the emission current showed a sharp decrease immediately after the surface cleaning. As a typical example, at a vacuum of 10 −9 torr, the current decreased to less than 10% of the initial value within 20 minutes.
ナノチューブやナノワイヤのような一次元ナノ構造体を用いて構成した新しいタイプの電界放出型電子源が作成された。各種のこのようなナノ構造は比較的不十分な真空環境においても数時間にわたって劣化のない電子放出特性を持っていることが示された。カーボンナノチューブ及び六ホウ化ランタン（ＬａＢ６）はこれらのうちでも注目すべき２つの例である。このような一次元ナノ構造体によって示された他の利点としては、放射された電子ビーム中のエネルギーの広がりが小さいという点が挙げられる。エネルギーの広がりが小さいと、電磁レンズによる電子ビームの収束が容易になり、分解能を上げることができる。 A new type of field emission electron source constructed using one-dimensional nanostructures such as nanotubes and nanowires has been created. A variety of such nanostructures have been shown to have electron emission characteristics without degradation over several hours even in relatively poor vacuum environments. Carbon nanotubes and lanthanum hexaboride (LaB 6 ) are two notable examples of these. Another advantage exhibited by such a one-dimensional nanostructure is that the energy spread in the emitted electron beam is small. When the spread of energy is small, the convergence of the electron beam by the electromagnetic lens becomes easy and the resolution can be increased.
しかしながら、ナノ構造体のサイズが小さいため、ナノ構造体をスポット溶接等によって電子放出器ホルダーベースに直接取り付けることができず、電子光学装置の電子源として使用するためには特別な取り扱い技法が必要とされた。 However, due to the small size of the nanostructure, the nanostructure cannot be directly attached to the electron emitter holder base by spot welding or the like, and special handling techniques are required to use it as an electron source for an electron optical device. It was said.
現行の技術では、針状の形状とした先端部材の表面上にこれらの一次元ナノ構造体を取り付ける。次に、この針状先端部材を従来の電子放出器ホルダに取り付ける。このような一次元ナノ構造体を使用した電子源全体構造の例を図１に示す。 In the current technology, these one-dimensional nanostructures are attached on the surface of the tip member having a needle shape. Next, this needle-like tip member is attached to a conventional electron emitter holder. An example of the entire structure of an electron source using such a one-dimensional nanostructure is shown in FIG.
しかし、針形状の先端部材側面は、そのままでは一次元ナノ構造体を接触させるだけで安定して付着させるのは困難であることが多い。そこで、特許文献１に示すように、針状先端部材に予め針の中心軸と平行な平坦部を形成しておき、この平坦部にＬａＢ６ナノワイヤー等の一次元ナノ構造体を付着させることが提案されている。これにより、一次元ナノ構造体とこの平面との間のファンデルワールス力等によって一次元ナノ構造はこの位置に比較的安定して付着するので、その後にスポット溶接等によってその場で固定するのに好都合である。 However, it is often difficult to stably attach the side surface of the needle-shaped tip member as it is simply by contacting the one-dimensional nanostructure. Therefore, as shown in Patent Document 1, a flat portion parallel to the central axis of the needle is formed in advance on the needle-like tip member, and a one-dimensional nanostructure such as LaB 6 nanowire is attached to the flat portion. Has been proposed. As a result, the one-dimensional nanostructure adheres relatively stably to this position due to the van der Waals force between the one-dimensional nanostructure and this plane, and is then fixed in place by spot welding or the like. Convenient to.
しかしながら、平坦部を設けるにせよ設けないにせよ、針先端部材側面に一次元ナノ構造を取り付ける構造ではナノ構造体は針状先端部材の一方の側面のみに取り付けられるので、電子放出器の先端部の形状は軸の周りに非対称となる。より具体的に説明すれば、平坦部の存在する構造では、特許文献１の図５を引用して示す図２から明らかなように、平坦部を設けるために切り欠きをそこに形成することで、当然、針状先端部材が針の中心軸の周りに非対称となる。また、平坦部を設けずに針状先端部材側面に一次元ナノ構造体を取り付けた場合には、一次元ナノ構造体を針状先端部材の軸に平行にしようとすると、当然ながら一次元ナノ構造体は先端部材の軸に対して斜行することになり、対称性が崩れてしまう。 However, in the structure in which the one-dimensional nanostructure is attached to the side surface of the needle tip member, whether or not the flat portion is provided, the nanostructure is attached only to one side surface of the needle-like tip member. The shape of is asymmetric about the axis. More specifically, in the structure in which the flat portion exists, as is clear from FIG. 2 that is cited with reference to FIG. 5 of Patent Document 1, a notch is formed therein to provide the flat portion. Of course, the needle-like tip member is asymmetric about the central axis of the needle. In addition, when a one-dimensional nanostructure is attached to the side surface of the needle-shaped tip member without providing a flat portion, it is natural that if the one-dimensional nanostructure is made parallel to the axis of the needle-shaped tip member, the one-dimensional nanostructure is The structure is inclined with respect to the axis of the tip member, and the symmetry is lost.
電子放出を行う際には、高い電圧を電子放出器の先端に印加し、電子ビームが取り出されるナノ構造体の先端部に高い電界を生成する。電子放出器先端が非対称であるとその周囲の電界が非対称になって、この電界により、電子ビームが電子光学系の光軸からずれてしまう。この現象は、ナノ構造体が針状先端部材先端から突出している長さが短い場合に特に甚だしいものとなる。一方では、最終的な電子プローブの不安定性をもたらすことになる振動を避けるためには、ナノ構造体の突出長をできるだけ短く抑える必要がある。従って、上述の非対称性の影響による電界の乱れの影響を軽減するためにナノ構造体先端を充分遠方まで突出させるという解決策は採用することができない。あるいは、非対称電界の影響による電子ビームの偏倚を補償するように電子放出器を傾斜させるという対策も一応は考えられる。しかし、この偏倚は個体毎のバラツキがあるため、補償のための傾斜は一律に設定できず、一次元ナノ構造体が取り付けられた先端部材毎に電子ビームの偏倚を測定して決める必要がある。従って、この対策は非常に煩雑かつ多大な調整工数を要することになり、現実的ではない。 When performing electron emission, a high voltage is applied to the tip of the electron emitter to generate a high electric field at the tip of the nanostructure from which the electron beam is extracted. If the tip of the electron emitter is asymmetric, the electric field around it becomes asymmetric, and this electric field shifts the electron beam from the optical axis of the electron optical system. This phenomenon is particularly severe when the length of the nanostructure protruding from the tip of the needle-like tip member is short. On the other hand, it is necessary to keep the protruding length of the nanostructure as short as possible in order to avoid vibrations that would cause instability of the final electron probe. Therefore, in order to reduce the influence of the disturbance of the electric field due to the influence of the asymmetry described above, it is not possible to adopt a solution in which the tip of the nanostructure protrudes far enough. Alternatively, it is conceivable that the electron emitter is tilted so as to compensate for the deviation of the electron beam due to the influence of the asymmetric electric field. However, since this deviation varies from individual to individual, the slope for compensation cannot be set uniformly, and it is necessary to determine the deviation of the electron beam for each tip member to which the one-dimensional nanostructure is attached. . Therefore, this measure is very complicated and requires a lot of adjustment man-hours, which is not realistic.
本発明の課題は、上述した従来技術の問題点を解消し、一次元ナノ構造体先端から電子ビームを放出する電子源の先端近傍の構造の非対称性が一次元ナノ構造体先端近傍の電界にもたらす非対称性を防止あるいは軽減することにある。 An object of the present invention is to solve the above-mentioned problems of the prior art, and the asymmetry of the structure near the tip of the electron source that emits an electron beam from the tip of the one-dimensional nanostructure becomes It is to prevent or reduce the resulting asymmetry.
本発明の一側面によれば、先端から電子ビームを放出する一次元ナノ構造体と、前記一次元ナノ構造体が取り付けられるとともに、前記電子ビーム放出方向軸の周りに非対称性を有する前記導電性先端部材とを設けた電子源において、前記導電性先端部材上であって、前記非対称性を有する部分よりも前記一次元ナノ構造体の前記先端寄りの位置に、前記電子ビーム放出方向軸の周りの対称性を有するとともに、中心に貫通孔を有する導電性軸対称部を設け、前記一次元ナノ構造体は前記貫通孔を通して前記導電性先端部材に取り付けられる電子源が与えられる。
ここで、前記導電性軸対称部はリング状の形状を有してよい。
また、前記一次元ナノ構造体はナノチューブまたはナノワイヤであってよい。
また、前記ナノチューブまたはナノワイヤはカーボンナノチューブ及び希土類六ホウ化物ナノワイヤからなる群から選択されてよい。
また、前記ナノチューブまたはナノワイヤは六ホウ化ランタンナノワイヤであってよい。
また、前記一次元ナノ構造体は前記導電性先端部材の材料との間の化学反応を抑制するバリア層を介して前記導電性先端部材に取り付けられてよい。
また、前記先端部材に平坦部が形成され、前記一次元ナノ構造体は前記平坦部上に取り付けられてよい。
また、前記先端部材と前記導電性軸対称部材とは一体構造であってよい。
また、前記電性軸対称部材は前記先端部材を収束イオンビーム加工することにより形成されてよい。
According to one aspect of the present invention, a one-dimensional nanostructure that emits an electron beam from a tip, and the conductive material having the one-dimensional nanostructure attached thereto and having asymmetry around the electron beam emission direction axis In an electron source provided with a tip member, around the electron beam emission direction axis on the conductive tip member and closer to the tip of the one-dimensional nanostructure than the asymmetric part The one-dimensional nanostructure is provided with an electron source that is attached to the conductive tip member through the through hole.
Here, the conductive axisymmetric portion may have a ring shape.
The one-dimensional nanostructure may be a nanotube or a nanowire.
The nanotubes or nanowires may be selected from the group consisting of carbon nanotubes and rare earth hexaboride nanowires.
The nanotube or nanowire may be a lanthanum hexaboride nanowire.
The one-dimensional nanostructure may be attached to the conductive tip member via a barrier layer that suppresses a chemical reaction with the material of the conductive tip member.
In addition, a flat portion may be formed on the tip member, and the one-dimensional nanostructure may be attached on the flat portion.
Further, the tip member and the conductive axisymmetric member may have an integral structure.
The electric axisymmetric member may be formed by subjecting the tip member to focused ion beam processing.
以上の構成により、本発明の電子源においては、一次元ナノ構造体を取り付ける先端部材の先端部あるいはその近傍に設けられた導電性軸対称構造物により、軸の周りの先端部材の非対称性が当該構造物よりも前方（電子ビーム放出方向）へ及ぼす影響を大きく低減できる。これにより、電子源の軸方向と一次元ナノ構造体からの電子ビーム放出方向とを容易に一致させることができるようになる。 With the above configuration, in the electron source of the present invention, the asymmetry of the tip member around the axis is caused by the conductive axisymmetric structure provided at or near the tip of the tip member to which the one-dimensional nanostructure is attached. The influence on the front side (electron beam emission direction) of the structure can be greatly reduced. As a result, the axial direction of the electron source and the electron beam emission direction from the one-dimensional nanostructure can be easily matched.
本発明の実施形態によれば、ナノワイヤやナノチューブなどの一次元方向に伸びるナノ材料、すなわち一次元ナノ構造体、が取り付けられる導電体の先端部材の非対称性による電界の非対称性が電子ビームの放射方向の意味で先端部材よりも先に及ばないようにする。具体的には先端部材に、電子ビームの放射方向軸の周りに対称な構造の軸対称導電性部材を設けることにより、これよりも後ろ側の非対称性の影響を静電シールドし、先へ及ばないようにする。この取り付け位置は先端部材の先端でもよいし、あるいは先端部材の先端付近の軸対称性が充分に高いのであれば、軸対称性の高い部分よりも後ろ側であってもよい。また、一次元ナノ構造体が軸対称導電性部材のほぼ中心を通るように配置する。そのため、軸対称導電性部材の中心は貫通孔が設けられている。従って、軸対称導電性部材の構造は、通常は図３に示すようにリング状の形状（リング状端部）として、一次元ナノ構造体取り付けのために平坦に形成されている先端部材の先端に取り付ける。 According to the embodiment of the present invention, the asymmetry of the electric field due to the asymmetry of the tip member of the conductor to which the nanomaterial extending in one dimension such as nanowire or nanotube, that is, the one-dimensional nanostructure, is attached is the emission of the electron beam. Do not extend beyond the tip member in terms of direction. Specifically, the tip member is provided with an axially symmetric conductive member having a symmetric structure around the radial axis of the electron beam, thereby electrostatically shielding the influence of asymmetry on the rear side of the tip member. Do not. This attachment position may be the tip of the tip member, or may be on the rear side of the portion with high axis symmetry if the axis symmetry near the tip of the tip member is sufficiently high. In addition, the one-dimensional nanostructure is disposed so as to pass through substantially the center of the axisymmetric conductive member. Therefore, a through hole is provided at the center of the axially symmetric conductive member. Therefore, the structure of the axially symmetric conductive member is usually a ring-shaped shape (ring-shaped end) as shown in FIG. 3, and the tip of the tip member is formed flat for attaching a one-dimensional nanostructure. Attach to.
なお、本発明では軸対称導電性部材以外は従来技術の一次元ナノ構造体を使用した電子源と同様な構造として良い。例えば、電子源の全体的な構造は図１に示した概念図と同じであって良い。従来技術におけるこの種の構造は当業者に周知であるため、本願明細書ではこれ以上の説明は行わないが、必要に応じて例えば特許文献１を参照されたい。 In addition, in this invention, it is good also as a structure similar to the electron source using the one-dimensional nanostructure of a prior art other than an axially symmetrical electroconductive member. For example, the overall structure of the electron source may be the same as the conceptual diagram shown in FIG. Since this type of structure in the prior art is well known to those skilled in the art, no further explanation is given here, but reference is made, for example, to US Pat.
以下、実施例により本発明をより詳細に説明する。ここで、以下の実施例はあくまでも本発明の理解を助けるために提示するものであり、これにより本発明を特定の構成に限定しようという意図はないことに注意されたい。 Hereinafter, the present invention will be described in more detail with reference to examples. Here, it should be noted that the following examples are provided only to help understanding of the present invention, and are not intended to limit the present invention to a specific configuration.
図４は、本発明の一実施例であるところの、一次元ナノ構造体としてＬａＢ６ナノワイヤを用いる電子源の製造方法の各ステップを説明するための概念図である。先ず収束イオンビーム（Focused Ion Beam；ＦＩＢ）技術を利用して、電子源の先端部材として使用する金属針の先端を加工することにより、そこにリング状先端部及びＬａＢ６ナノワイヤを取り付けるための平坦部を形成する。このとき、リングの中心線（リングの貫通孔（開口部）により画定される円盤面の中心を通り、円盤面に垂直な直線）はほぼ針の側面に形成された平坦部の平面を通るように加工するのが望ましい。これらを形成した後の金属針の先端付近を図４（ａ）に示す。次に、ステップ（ａ）では、ＳＥＭの試料室内に置かれたＦＩＢ加工後の金属針上のリング状先端部及び一本のＬａＢ６ナノワイヤを同じく試料室内に置かれたマニピュレーターで把持する。この様子を図４（ｂ）に示す。なお、図４（ｂ）並びにその後のステップである（ｃ）及び（ｄ）中の左右にそれぞれ一つずつ置かれた灰色の円はマニピュレーターによる把持位置を示す。次に、マニピュレーターの操作により、把持されているＬａＢ６ナノワイヤを金属針先端のリング状先端部の孔に通し、その先にある金属針側面上の平坦部に接触させる。両者が近接した際に働くファンデルワールス力により、ＬａＢ６ナノワイヤは平坦部に付着する。この時、ＬａＢ６ナノワイヤをリングの中心線にほぼ一致するように位置決めするのが望ましい。この様子を図４（ｃ）に示す。この状態で、電子ビームを用いて固定パッド（図３も参照のこと）をＬａＢ６ナノワイヤ上にデポジットすることにより、ＬａＢ６ナノワイヤを金属針の平坦部にしっかりと固定する。最後に、完成したＬａＢ６ナノワイヤ電子源をマニピュレーターから取り外す。この様子を図４（ｅ）に示す。 FIG. 4 is a conceptual diagram for explaining each step of a method of manufacturing an electron source using LaB 6 nanowires as a one-dimensional nanostructure, which is an embodiment of the present invention. First, using a focused ion beam (FIB) technique, the tip of a metal needle used as a tip member of an electron source is processed, and a flat surface for attaching a ring-shaped tip and LaB 6 nanowires thereto. Forming part. At this time, the center line of the ring (a straight line passing through the center of the disk surface defined by the through-hole (opening) of the ring and perpendicular to the disk surface) passes through the plane of the flat part formed on the side surface of the needle. It is desirable to process it. FIG. 4A shows the vicinity of the tip of the metal needle after these are formed. Next, in step (a), the ring-shaped tip on the metal needle after FIB processing placed in the sample chamber of the SEM and one LaB 6 nanowire are held by a manipulator also placed in the sample chamber. This is shown in FIG. 4B and the subsequent steps (c) and (d), the gray circles placed one on each of the left and right indicate the gripping position by the manipulator. Next, by operating the manipulator, the grasped LaB 6 nanowire is passed through the hole in the ring-shaped tip of the metal needle tip and brought into contact with the flat part on the side surface of the metal needle. The LaB 6 nanowire adheres to the flat part due to the van der Waals force that acts when both come close to each other. At this time, it is desirable to position the LaB 6 nanowire so as to substantially coincide with the center line of the ring. This situation is shown in FIG. In this state, the LaB 6 nanowire is firmly fixed to the flat portion of the metal needle by depositing a fixing pad (see also FIG. 3) on the LaB 6 nanowire using an electron beam. Finally, the completed LaB 6 nanowire electron source is removed from the manipulator. This is shown in FIG.
ここで、金属針の材料としては従来技術で使用されている材料、例えばタンタル、を使用することができる。また、ＬａＢ６（より一般的には一次元ナノ構造体の材料）と反応する金属、例えばタングステン、であっても、カーボン等の導電性のバリア層を介してＬａＢ６ナノワイヤを取り付けることができる。本願で先端部材と言う場合には、このようなバリア層まで含めるものとする。 Here, as the material of the metal needle, a material used in the prior art, such as tantalum, can be used. The metal which reacts with LaB 6 (more common material of one dimensional nanostructures on), for example, tungsten, even, it is possible to attach the LaB 6 nanowires via a conductive barrier layer, such as carbon . In the present application, the term “tip member” includes such a barrier layer.
このようにして作製したＬａＢ６ナノワイヤ電子源の実施例の先端近傍のＳＥＭ像を図５（ａ）に示す。このＳＥＭ像からわかるように、リング状先端部は幾何学的に完全な円形のリングである必要はなく、また一次元ナノ構造体がリングのちょうど中心を通ることも必須であるわけではない。リング状先端部の形状や一次元ナノ構造体の貫通位置は、一次元ナノ構造体先端付近及びそこから放出される電子ビーム経路近傍の電界が、電子ビームの進路に有害な偏倚をもたらさないよう、充分な軸対称性を有するものであればよいことに注意されたい。 FIG. 5A shows an SEM image in the vicinity of the tip of the LaB 6 nanowire electron source produced as described above. As can be seen from this SEM image, the ring-shaped tip need not be a geometrically perfect circular ring, and it is not essential that the one-dimensional nanostructure pass through the exact center of the ring. The shape of the ring-shaped tip and the penetration position of the one-dimensional nanostructure are such that the electric field in the vicinity of the tip of the one-dimensional nanostructure and the electron beam path emitted from the tip does not cause a detrimental deviation in the path of the electron beam. It should be noted that it is sufficient if it has sufficient axial symmetry.
比較対象として、図５（ｂ）には、リング状先端部を有していない、金属針の先端付近に形成した平坦部にＬａＢ６ナノワイヤを固定しただけの従来構造の電子源の先端付近のＳＥＭ像を示す。両者を見比べるだけで、図５（ａ）に示す本発明実施例の構造の方が、リング状先端部による静電シールド効果により金属針側面に形成された軸対称性のない平坦部の影響が遮断されるために、突出したＬａＢ６ナノワイヤ周囲の電界の軸対称性が遙かに高くなることが理解できるであろう。 As a comparison object, FIG. 5B shows the vicinity of the tip of an electron source having a conventional structure in which a LaB 6 nanowire is fixed to a flat portion formed in the vicinity of the tip of a metal needle that does not have a ring-shaped tip. An SEM image is shown. By comparing the two, the structure of the embodiment of the present invention shown in FIG. 5A is affected by the flat portion having no axial symmetry formed on the side surface of the metal needle due to the electrostatic shielding effect by the ring-shaped tip. It can be seen that the axial symmetry of the electric field around the protruding LaB 6 nanowires is much higher due to being blocked.
この直感的な理解は、数値計算で求めた電界分布及びそれによる電子ビームの本来の放出軸方向（つまり、上述のようなわずかな非対称性による外乱の影響を考えずに設定した放出軸の方向。電子源を使用する場合にはこの放出方向を電子光学系の光軸に整列させるため、本願ではこの放出軸を光軸とも称する）からの偏倚を図形表現した結果から確認される。図５（ａ）に示す構造を有する本発明の実施例の電界分布及び電子ビームの光軸からの偏倚をそれぞれ図６Ａ（ａ）及び（ｂ）に、また図５（ｂ）に示す従来構造の場合についての対応する電界分布及び偏倚をそれぞれ図６Ｂ（ａ）及び（ｂ）に示す。図６Ａ（ａ）及び図６Ｂ（ａ）において、金属針の先端は図の上端付近にあり、そこからＬａＢ６ナノワイヤが下向きに伸びてそれぞれの図の中心に至る。この先端から下に向かって伸びている細い直線はＬａＢ６ナノワイヤの先端から放出される電子ビームを示す。図６Ａ（ａ）に示す本発明の実施例の電界分布は、リング状部から下の領域で左右対称（三次元空間で見ればＬａＢ６ナノワイヤの中心軸の周りに回転対称）になっていることがわかる。これに対して、従来構造の場合の電界分布を示す図６Ｂ（ａ）では、針先端付近に形成された平坦部の影響により、ＬａＢ６ナノワイヤの先端に至ってもまだ電界の非対称性が残留している。図６Ａ（ａ）及び図６Ｂ（ａ）の下部に、中心軸がそれぞれの図の下部外枠と交差する位置を０とし、そこから左右への距離を示す。本発明の実施例の場合を示す図６Ａ（ａ）では電子ビームが光軸の位置であるちょうど０の位置を通っている。これに対して、従来構成の場合の図６Ｂ（ａ）では、電子ビームが下部外枠と交差する点は０位置から僅かに左にずれている。この交差位置付近を拡大することでそれぞれの電子ビーム軌道の偏倚を見やすく示す図である図６Ａ（ｂ）及び図６Ｂ（ｂ）から、実施例の電子ビームがちょうど０位置を通っているのに対して、従来構造の電子源からの電子ビームは光軸からの偏倚は約−４０であることがわかる。 This intuitive understanding is based on the electric field distribution obtained by numerical calculation and the original emission axis direction of the electron beam (that is, the direction of the emission axis set without considering the influence of disturbance due to the slight asymmetry as described above) In the case of using an electron source, this emission direction is aligned with the optical axis of the electron optical system, and in this application, this emission axis is also referred to as an optical axis). The electric field distribution and the deviation of the electron beam from the optical axis in the embodiment of the present invention having the structure shown in FIG. 5A are shown in FIGS. 6A and 6B, respectively, and in the conventional structure shown in FIG. The corresponding electric field distributions and deviations for the case are shown in FIGS. 6B (a) and 6 (b), respectively. 6A (a) and 6B (a), the tip of the metal needle is near the upper end of the figure, from which LaB 6 nanowires extend downward to reach the center of each figure. A thin straight line extending downward from the tip indicates an electron beam emitted from the tip of the LaB 6 nanowire. The electric field distribution of the embodiment of the present invention shown in FIG. 6A (a) is symmetrical in the region below the ring-shaped portion (rotationally symmetric about the central axis of the LaB 6 nanowire in a three-dimensional space). I understand that. On the other hand, in FIG. 6B (a) showing the electric field distribution in the case of the conventional structure, the electric field asymmetry still remains even when reaching the tip of the LaB 6 nanowire due to the influence of the flat portion formed near the tip of the needle. ing. 6A (a) and 6B (a), the position where the central axis intersects with the lower outer frame of each figure is 0, and the distance from the left to the right is shown. In FIG. 6A (a) showing the case of the embodiment of the present invention, the electron beam passes through the position of 0, which is the position of the optical axis. On the other hand, in FIG. 6B (a) in the case of the conventional configuration, the point where the electron beam intersects the lower outer frame is slightly shifted to the left from the 0 position. 6A (b) and FIG. 6B (b), which show the deviation of each electron beam trajectory in an easy-to-see manner by enlarging the vicinity of this intersection position, although the electron beam of the example passes just the 0 position. On the other hand, it can be seen that the electron beam from the electron source having the conventional structure has a deviation of about −40 from the optical axis.
図７は、本発明の図５（ａ）に示す構造の一実施例及び図５（ｂ）に示す従来構成の電子源から放出された電子ビームをそれぞれマイクロチャンネルプレート（Micro-channel Plate、ＭＣＰ）で観測した結果を示す。図７（ａ）にこの観測のための測定系機器構成を示す。実施例または従来構造の電子源の光軸がＭＣＰの中心を通るように両者を正対させて配置した。その結果ＭＣＰから得られた出力パターンをそれぞれ図７（ｂ）及び図７（ｃ）に示す。両図の中心の円はＭＣＰの中心孔を示す。本発明の実施例からの電子ビームの観測結果を示す図７（ｂ）では電子ビーム照射位置を示す明るい部分がＭＣＰの中心孔位置と一致し、電子ビームの偏倚がなかったことがわかる。これに対して、従来構成の電子源からの電子ビームの観測結果を示す図７（ｃ）では電子ビーム照射位置はＭＣＰの中心孔から左下方向にかなりずれた位置になっていた。これにより、従来構成では上で縷々説明した電界の非対称性により大きな偏倚が生じることが実証された。 FIG. 7 shows an embodiment of the structure shown in FIG. 5 (a) of the present invention and an electron beam emitted from the electron source having the conventional structure shown in FIG. 5 (b), respectively, as a micro-channel plate (MCP). ) Shows the observation results. FIG. 7A shows the measurement system equipment configuration for this observation. Both were arranged so that the optical axis of the electron source of the example or the conventional structure passed through the center of the MCP. As a result, the output patterns obtained from the MCP are shown in FIGS. 7B and 7C, respectively. The center circle in both figures represents the central hole of the MCP. In FIG. 7B showing the observation result of the electron beam from the example of the present invention, it can be seen that the bright part indicating the electron beam irradiation position coincides with the center hole position of the MCP, and there is no deviation of the electron beam. On the other hand, in FIG. 7C, which shows the observation result of the electron beam from the electron source of the conventional configuration, the electron beam irradiation position is considerably shifted in the lower left direction from the central hole of the MCP. This proves that a large deviation occurs in the conventional configuration due to the electric field asymmetry often described above.
各部のサイズを変化させた本発明の実施例のＬａＢ６ナノワイヤを使用した電子源を６基作成して、それぞれのサイズ及びその電子ビーム軸偏角（電子ビームが光軸に対してなす角。電子ビームが光軸に完全に一致した場合は０°）を測定した。その結果を以下の表に示す。 Six electron sources using the LaB 6 nanowire of the embodiment of the present invention in which the size of each part was changed were prepared, and each size and its electron beam axis deflection angle (angle formed by the electron beam with respect to the optical axis). When the electron beam completely coincided with the optical axis, 0 °) was measured. The results are shown in the following table.
原理的には、ナノワイヤ突出長が長いほど（つまり、ナノワイヤ先端が針の非対称性による電界の乱れから遠方にあるほど）、またリング外径が大きいほど（つまり、静電シールド部が大きいほど）、電子ビームへの非対称性の影響が小さくなり、電子ビーム軸偏角が小さくなるはずである。しかしながら、実際の測定結果は、突出長及びリング外径が広い範囲で変化しても電子ビーム軸偏角は充分に小さな値を維持した。これは、軸非対称性を有する部分とナノ構造体先端との間に比較的小さな軸対称部材を置くだけで、電界の軸対称性の乱れに対する充分に高いシールド効果が発揮されることを示している。 In principle, the longer the nanowire protrusion length (that is, the farther the tip of the nanowire is from the disturbance of the electric field due to the asymmetry of the needle), the larger the outer ring diameter (that is, the larger the electrostatic shield part) The influence of asymmetry on the electron beam should be reduced, and the electron beam axis deflection angle should be reduced. However, the actual measurement results showed that the electron beam axis declination maintained a sufficiently small value even when the protrusion length and the ring outer diameter varied in a wide range. This indicates that a sufficiently high shielding effect against the disturbance of the axial symmetry of the electric field can be exerted only by placing a relatively small axisymmetric member between the portion having axial asymmetry and the tip of the nanostructure. Yes.
以上、本発明を実施例に基づいて説明したが、既に述べたように本発明は上記実施例に限定されるものではない。例えば、上記実施例では一次元ナノ構造体としてＬａＢ６ナノワイヤを使用したが、例えばカーボンナノチューブ、希土類六ホウ化物ナノワイヤ等の従来技術の電子線源に使用できる一次元ナノ構造体であれば本発明にも同様に使用できる。また、金属針（先端部材）には必ずしも一次元ナノ構造体を取り付けやすくするための平坦部分を設ける必要はないし、またこのような取り付けを助けるための構造を設けるとしても平坦部材に限られるものではない。更に、冷陰極電界放出型電子源に関して本発明を説明したが、本発明はこの形式の電子源に限定されるものではなく、その先端付近に何らかの態様で印加される電界の軸対称性の乱れが電子ビームの軌道に悪影響を与えるような電子源に対して適用することができることにも注意されたい。 The present invention has been described based on the embodiments. However, as described above, the present invention is not limited to the above embodiments. For example, although LaB 6 nanowires are used as the one-dimensional nanostructures in the above embodiments, the present invention is applicable to any one-dimensional nanostructures that can be used for conventional electron beam sources such as carbon nanotubes and rare earth hexaboride nanowires. Can be used in the same way. In addition, it is not always necessary to provide a flat portion on the metal needle (tip member) to facilitate attachment of the one-dimensional nanostructure, and even if a structure for assisting such attachment is provided, it is limited to the flat member. is not. Furthermore, although the present invention has been described with reference to a cold cathode field emission electron source, the present invention is not limited to this type of electron source, and the axial symmetry of the electric field applied in some manner near the tip thereof is disturbed. It should also be noted that can be applied to electron sources that adversely affect the trajectory of the electron beam.
以上詳細に説明したように、本発明によれば電子源の形状の非対称性が電子源から放出される電子ビームの方向に与える悪影響を防止あるいは大幅に軽減することができるため、電子源の各種の応用にとって大きな貢献をもたらすことが期待される。 As described above in detail, according to the present invention, the asymmetry of the shape of the electron source can prevent or significantly reduce the adverse effect on the direction of the electron beam emitted from the electron source. It is expected to make a significant contribution to the application of.
Claims (9)
前記一次元ナノ構造体が取り付けられるとともに、前記電子ビーム放出方向軸の周りに非対称性を有する前記導電性先端部材と、
を設けた電子源において、
前記導電性先端部材上であって、前記非対称性を有する部分よりも前記一次元ナノ構造体の前記先端寄りの位置に、前記電子ビーム放出方向軸の周りの対称性を有するとともに、中心に貫通孔を有する導電性軸対称部を設け、
前記一次元ナノ構造体は前記貫通孔を通して前記導電性先端部材に取り付けられる
電子源。 A one-dimensional nanostructure that emits an electron beam from a tip; and the conductive tip member that is attached to the one-dimensional nanostructure and has asymmetry around the electron beam emission direction axis;
In an electron source with
It has symmetry around the electron beam emission direction axis and penetrates to the center at a position closer to the tip of the one-dimensional nanostructure than the portion having the asymmetry on the conductive tip member. Provide a conductive axisymmetric part with holes,
The one-dimensional nanostructure is an electron source attached to the conductive tip member through the through hole.
前記一次元ナノ構造体は前記平坦部上に取り付けられる
請求項１から６の何れかに記載の電子源。 A flat portion is formed on the tip member;
The electron source according to claim 1, wherein the one-dimensional nanostructure is attached on the flat portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014244963A JP6369987B2 (en) | 2014-12-03 | 2014-12-03 | Electron source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014244963A JP6369987B2 (en) | 2014-12-03 | 2014-12-03 | Electron source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2016110748A JP2016110748A (en) | 2016-06-20 |
| JP6369987B2 true JP6369987B2 (en) | 2018-08-08 |
Family
ID=56124562
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2014244963A Active JP6369987B2 (en) | 2014-12-03 | 2014-12-03 | Electron source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6369987B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7145533B2 (en) * | 2019-01-30 | 2022-10-03 | 国立研究開発法人物質・材料研究機構 | Emitters, electron guns and electronic devices using them |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3832402B2 (en) * | 2002-08-12 | 2006-10-11 | 株式会社日立製作所 | Electron source having carbon nanotubes, electron microscope and electron beam drawing apparatus using the same |
| JP4446667B2 (en) * | 2003-02-14 | 2010-04-07 | 敬義 丹司 | CNT (carbon nanotube) chip, method for manufacturing the same, electron gun, and probe for scanning probe microscope |
| US7544523B2 (en) * | 2005-12-23 | 2009-06-09 | Fei Company | Method of fabricating nanodevices |
| JP5102968B2 (en) * | 2006-04-14 | 2012-12-19 | 株式会社日立ハイテクノロジーズ | Conductive needle and method of manufacturing the same |
| JP4895938B2 (en) * | 2007-07-24 | 2012-03-14 | 株式会社日立ハイテクノロジーズ | Field emission electron gun and electron beam application apparatus using the same |
-
2014
- 2014-12-03 JP JP2014244963A patent/JP6369987B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2016110748A (en) | 2016-06-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5850984B2 (en) | Method for imaging a sample in a charged particle device | |
| JP4227646B2 (en) | Electron beam source and electron beam application device | |
| KR20040014912A (en) | Emission source having carbon nanotube, electronic microscope and electronic beam lithographic device using the same | |
| JP6608367B2 (en) | Field emission device, system and method | |
| US7732764B2 (en) | Field emission electron gun and electron beam applied device using the same | |
| CN110291609A (en) | Electron beam emitter with ruthenium coating | |
| Zhang et al. | High-endurance micro-engineered LaB6 nanowire electron source for high-resolution electron microscopy | |
| JP4782736B2 (en) | Electron source | |
| JP7442299B2 (en) | Electron gun, electron emission device, and method for manufacturing an electron gun | |
| JP3982558B2 (en) | Electron source having carbon nanotubes, electron microscope and electron beam drawing apparatus using the same | |
| JP6369987B2 (en) | Electron source | |
| US11915920B2 (en) | Emitter, electron gun in which same is used, electronic device in which same is used, and method for manufacturing same | |
| TWI712066B (en) | Electron beam device, thermal field emitter, method for producing an emitter tip for a thermal field emitter, and method for operating an electron beam device | |
| JP6028277B2 (en) | Metal boride field emitter fabrication method | |
| US9633815B1 (en) | Emitter for an electron beam, electron beam device and method for producing and operating an electron emitter | |
| US9093243B2 (en) | Gun configured to generate charged particles | |
| KR20190028547A (en) | Electron source and electron beam irradiator | |
| US11721516B2 (en) | Emitter, electron gun using same, and electronic device | |
| JP6038794B2 (en) | Electron gun that emits under high voltage, configured for electron microscopy | |
| JP4914178B2 (en) | Schottky electron gun and charged particle beam apparatus equipped with Schottky electron gun | |
| Fujieda et al. | Direct observation of field emission sites in a single multiwalled carbon nanotube by Lorenz microscopy | |
| KR20120130999A (en) | Multi-beam X-ray tube | |
| JPWO2020115825A1 (en) | Charged particle source, charged particle beam device | |
| KR101864219B1 (en) | Field Emitter | |
| JP7168269B2 (en) | EMITTER, ELECTRON GUN USING IT, ELECTRONIC DEVICE USING SAME, AND MANUFACTURING METHOD THEREOF |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20170920 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20180626 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20180709 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6369987 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |