JPH0461724A - Manufacture of niobium carbide field emitter - Google Patents
Manufacture of niobium carbide field emitterInfo
- Publication number
- JPH0461724A JPH0461724A JP2168066A JP16806690A JPH0461724A JP H0461724 A JPH0461724 A JP H0461724A JP 2168066 A JP2168066 A JP 2168066A JP 16806690 A JP16806690 A JP 16806690A JP H0461724 A JPH0461724 A JP H0461724A
- Authority
- JP
- Japan
- Prior art keywords
- torr
- emitter
- current
- field emitter
- niobium carbide
- 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.)
- Granted
Links
- UNASZPQZIFZUSI-UHFFFAOYSA-N methylidyneniobium Chemical compound [Nb]#C UNASZPQZIFZUSI-UHFFFAOYSA-N 0.000 title claims description 9
- 238000004519 manufacturing process Methods 0.000 title description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 10
- 239000010439 graphite Substances 0.000 claims abstract description 10
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000005977 Ethylene Substances 0.000 claims abstract description 7
- 239000013078 crystal Substances 0.000 claims abstract description 7
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 7
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 7
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 6
- 230000005684 electric field Effects 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims 1
- 230000006641 stabilisation Effects 0.000 abstract description 2
- 238000011105 stabilization Methods 0.000 abstract description 2
- 230000005855 radiation Effects 0.000 description 11
- 238000010438 heat treatment Methods 0.000 description 10
- 229910052758 niobium Inorganic materials 0.000 description 3
- 239000010955 niobium Substances 0.000 description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 3
- 230000001747 exhibiting effect Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000001427 coherent effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は高安定電流特性を示す炭化ニオブフィールドエ
ミッターの作製方法に関する。このフィールドエミッタ
ーは、高輝度、可干渉性点光源として使用可能であり、
例えば、低加速走査電子顕微鏡、分析電子顕微鏡等の電
子源として重要である。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a niobium carbide field emitter exhibiting highly stable current characteristics. This field emitter can be used as a high-brightness, coherent point light source,
For example, it is important as an electron source for low-acceleration scanning electron microscopes, analytical electron microscopes, and the like.
（従来の技術及び解決しようとする課題）従来、フィー
ルドエミッターとして、タングステン（Ｗ）金属単結晶
が実用化されているが、とのＷフィールドエミッターは
時間と共に大幅に電流が減衰すると共にｌ／ｆノイズも
大きいので広い応用を阻害している。(Prior art and problems to be solved) Conventionally, tungsten (W) metal single crystal has been put into practical use as a field emitter, but the current of the W field emitter decreases significantly over time and l/f The noise is also large, which hinders its wide application.
そこで、本発明者らは、この問題点を解消すべく研究を
重ねた結果、電子放射特性のよい炭窒化ニオブフィール
ドエミッターを開発した（特願昭６２−１１３３３４号
、特願昭６３−０３５７９４号）。As a result of repeated research to solve this problem, the inventors of the present invention developed a niobium carbonitride field emitter with good electron emission characteristics (Japanese Patent Application No. 113334/1982, No. 035794/1983). ).
しかし、このフィールドエミッターの高輝度性を利用す
るためには、Ｉ Ｘ １０−”Ｔｏｒｒの圧力のもとて
約２０μＡ以上の電流を安定に放射することが難しいと
いう問題があった。However, in order to take advantage of the high brightness of this field emitter, there is a problem in that it is difficult to stably emit a current of about 20 μA or more under a pressure of I x 10-'' Torr.
本発明は、上記炭窒化ニオブフィールドエミッターの問
題点を解消すべくなされたものであって、１ｘ１０″″
１０Ｔｏｒｒにおいて、約２０μＡ以上の電流を安定に
放射し得る新規なフィールドエミッターの作製方法を提
供することを目的とするものである。The present invention has been made to solve the problems of the above-mentioned niobium carbonitride field emitter.
The object of the present invention is to provide a method for producing a novel field emitter that can stably emit a current of about 20 μA or more at 10 Torr.
（課題を解決するための手段）
本発明者らは、前記目的を達成すべく、更に研究を続け
た結果、炭窒化ニオブに代えて、炭化ニオブ単結晶エミ
ッターを用いるに際し、これに特定の処理を施すことに
より、エミッションパターンが変化し、Ｉ Ｘ Ｉ ０
−１０Ｔｏｒｒにおいて約５０μＡの電流を安定に放射
することを見い出し、この知見に基づき本発明を完成し
たものである。(Means for Solving the Problems) In order to achieve the above object, the present inventors continued their research and found that when using a niobium carbide single crystal emitter instead of niobium carbonitride, a specific treatment is applied to it. By applying , the emission pattern changes and I
It was discovered that a current of approximately 50 μA can be stably emitted at -10 Torr, and the present invention was completed based on this knowledge.
すなわち、本発明は、炭化ニオブ単結晶エミッターを、
１４００〜１８００℃のもとで、エチレンその他の炭化
水素系ガスに５０００Ｌ以上露出し、その表面にグラフ
ァイト膜を形成させた後、超高真空下で１０＠ｖ／ｃｌ
１以上の強電界を印加することを特徴とする高安定電子
放射特性を示す炭化ニオブフィールドエミッターの作製
方法を要旨とするものである。That is, the present invention uses a niobium carbide single crystal emitter,
After being exposed to 5000L or more of ethylene or other hydrocarbon gas at 1400-1800℃ to form a graphite film on the surface, it was exposed to 10@v/cl under ultra-high vacuum.
The gist of the present invention is a method for producing a niobium carbide field emitter exhibiting highly stable electron emission characteristics, which is characterized by applying one or more strong electric fields.
以下に本発明を更に詳述する。The present invention will be explained in further detail below.
（作用）
本発明において使用する炭化ニオブ単結晶エミッター（
以下、ｒＮｂＣエミッター」と記載する）は、例えば、
０．２ａｖ＋Ｘ０．２ｍｍＸ３＋ｎｍ（７）直方体単
結晶の先端を電解研磨法により約０．１．ｕｎの先端径
とし、これを超高真空中で１５００〜１９００℃でフラ
ッシュ加熱することで得られる。この加熱により清浄表
面にすると共にチップ先端を（１００）、（１１１）面
で覆われた多面体形状にできる。例えば、エミッター軸
を＜１１０＞方位とするエミッターの場合は、そのチッ
プ形状は第１［１に示すような多面体形状になる。この
エミッターからのエミッションパターンは第２図に示す
とおりである。斜線部分は電子ビームのあたった部分を
示している。(Function) Niobium carbide single crystal emitter used in the present invention (
Hereinafter referred to as "rNbC emitter"), for example,
0.2 av+ The diameter of the tip of un is obtained by flash heating at 1500 to 1900°C in an ultra-high vacuum. This heating makes the surface clean and allows the tip end of the chip to have a polyhedral shape covered with (100) and (111) planes. For example, in the case of an emitter whose emitter axis is in the <110> direction, the chip shape is a polyhedral shape as shown in the first [1]. The emission pattern from this emitter is as shown in FIG. The shaded area indicates the area hit by the electron beam.
得られたＮｂＣ＜１１０＞エミッターのチップを、まず
、エチレン又はその他の炭化水素ガス（圧力Ｉ Ｘ １
０−＠Ｔｏｒｒ）中で、１４００〜１８００℃の範囲の
温度で５０００秒以上、すなわち、５０００Ｌ以上加熱
（露出）する。ここで、ＬＬ＝Ｉ Ｘ Ｉ Ｑ −”
Ｔｏｒｒ・秒である。これにより、表面にグラファイト
膜が形成される。The obtained NbC<110> emitter chip was first heated with ethylene or other hydrocarbon gas (pressure I
0-@Torr) at a temperature in the range of 1400 to 1800° C. for 5000 seconds or more, that is, 5000 L or more. Here, LL=I X I Q −”
It is Torr·sec. This forms a graphite film on the surface.
次に超高真空Ｃ例、Ｉ Ｘ １０−１０Ｔｏｒｒ）に排
気し、１０”Ｖ／ｃｍ以上の強電界、を印加する。この
操作により、エミッションパターンは第２図から第３図
のように変化すると共に放射電流の安定化が起こる。Next, evacuate to an ultra-high vacuum (I x 10-10 Torr) and apply a strong electric field of 10"V/cm or more. Through this operation, the emission pattern changes as shown in Figures 2 and 3. At the same time, stabilization of the radiation current occurs.
これらの条件を限定した理由は以下のとおりである。The reason for limiting these conditions is as follows.
まず、前記のガス中での加熱温度は、１４００〜１８０
０℃の範囲であることが必要である。加熱温度が１４０
０’Ｃ未満ではチップ先端の（１１１）面にのみグラフ
ァイトが生成し、放射電流の安定性に欠ける。一方、加
熱温度が１８００”Ｃ以上ではグラファイトが昇華し、
チップ先端の表面にはグラファイトが生成せず、放射電
流の安定化が起こらない、加熱温度が１４００〜１８０
０”Ｃの範囲の場合において、チップ先端の（１１１）
、（１００）面上にグラファイトが生成し、放射電流が
極めて安定になる。この範囲の温度であると、短時間ノ
イズが±０．２％以下、ドリフトは±０゜１％／ｈｒ以
下と電流安定性が極めてよく、因みに１ Ｘ １０−１
ｏＴｏｒｒのもとでは、５０．［ＪＡの放射電流が第４
図に示すように安定に得られ、フィールドエミッターの
高輝度性を有効に利用することが可能となる。First, the heating temperature in the gas is 1400 to 180.
It is necessary that the temperature is in the range of 0°C. Heating temperature is 140
If the temperature is less than 0'C, graphite is generated only on the (111) plane at the tip of the chip, resulting in a lack of stability in the radiation current. On the other hand, when the heating temperature is 1800"C or higher, graphite sublimes,
Graphite is not generated on the surface of the tip of the tip, and the radiation current does not stabilize when the heating temperature is 1400 to 180℃.
In the case of 0”C range, (111) of the tip tip
, graphite is generated on the (100) plane, and the radiation current becomes extremely stable. When the temperature is in this range, the short-time noise is less than ±0.2%, the drift is less than ±0°1%/hr, and the current stability is extremely good.
Under oTorr, 50. [The radiation current of JA is the fourth
As shown in the figure, it can be stably obtained and the high brightness of the field emitter can be effectively utilized.
エチレン又はその他の炭化水素ガス（圧力１×１０−’
Ｔｏｒｒ）中での加熱時間は５０００秒以上であるこ
とが必要である。これは、５０００秒以下ではチップ先
端の（１１１）面にのみグラファイトが生成し、加熱温
度が１４００”Ｃ未満の場合と同様に、放射電流の安定
性はよくないためである。Ethylene or other hydrocarbon gas (pressure 1 x 10-'
It is necessary that the heating time in (Torr) is 5000 seconds or more. This is because graphite is generated only on the (111) plane at the tip of the chip for less than 5000 seconds, and the stability of the radiation current is not good as in the case where the heating temperature is less than 1400''C.
炭化水素ガスとしては、エチレンの他、メタン等の炭化
水素が挙げられる。Examples of the hydrocarbon gas include hydrocarbons such as methane in addition to ethylene.
次に本発明の実施例を示す。Next, examples of the present invention will be shown.
（実施例）
先端径０．１ μｍ（７）ＮｂＣ＜１１０＞ １ミツタ
ーを超高真空下（Ｉ Ｘ １０″″１ｏＴｏｒｒ）の下
で、１８００℃でフラッシュ加熱して清浄表面とした。(Example) A NbC<110> 1 meter with a tip diameter of 0.1 μm was flash-heated at 1800° C. under an ultra-high vacuum (I x 10″″1oTorr) to give a clean surface.
次いで、この系にエチレンガスを導入し、１×１０−”
Ｔｏｒｒの圧力下においてチップを１５００℃で２
Ｘ １０’秒加熱して、チップ表面にグラファイトを生
成させた。この後、超高真空に排気してエミッターに１
０＠Ｖ／ｃｍ以上の電界を印加してエミッションパター
ンを第２図から第３図に変化させた。Next, ethylene gas was introduced into the system to produce 1×10-”
The chips were heated at 1500°C under a pressure of Torr for 2
The chip was heated for 10' seconds to generate graphite on the chip surface. After this, evacuate to ultra-high vacuum and put 1
The emission pattern was changed from FIG. 2 to FIG. 3 by applying an electric field of 0@V/cm or more.
得られたフィールドエミッターの電流特性は、Ｉ×１０
″″１０Ｔｏｒｒの真空度、５０μＡの放射電流のもと
で、第４図に示すように、短時間ノイズが±０．２％以
下、ドリフトは±０．１％／ｈｒ以下と極めて安定であ
った。また、より小さい放射電流では、より長時間安定
に放射できた。The current characteristics of the obtained field emitter are I×10
As shown in Figure 4, under a vacuum of 10 Torr and a radiation current of 50 μA, the short-time noise is less than ±0.2% and the drift is less than ±0.1%/hr, making it extremely stable. Ta. Furthermore, with a smaller radiation current, stable radiation could be achieved for a longer period of time.
（発明の効果）
以上説明したように、本発明の方法によれば、Ｉ Ｘ
１０−１０Ｔｏｒｒの真空度、５０μＡの放射電流でも
短時間ノイズは±０．２％以下、ドリフトは±０．１％
／ｈｒ以下と極めて安定であり、しかもこれを再現性よ
く得られる炭化ニオブフィールドエミッターを提供でき
る。(Effect of the invention) As explained above, according to the method of the present invention, I
Even with a vacuum level of 10-10 Torr and a radiation current of 50 μA, short-time noise is less than ±0.2% and drift is ±0.1%.
It is possible to provide a niobium carbide field emitter that is extremely stable at less than /hr and can be obtained with good reproducibility.
第１図はＮｂＣ＜１１０＞フィールドエミッターを１８
００℃でフラッシュ加熱後のチップ先端形状を示す図、
第２図は１８００℃でフラッシュ加熱後のエミッターか
らのエミッションパターンを示す図、第３図は本発明の
方法で得られるフィールドエミッターのエミッションパ
ターンを示す図、第４図は本発明の実施例で得られたフ
ィールドエミッターの全放射電流経時変化（真空度は１
×１０−１０Ｔｏｒｒ）を示す図である。
特許出願人 科学技術庁無機材質研、究所長瀬高信雄
第１図
第
図
第２図
第３図
時間（分）Figure 1 shows 18 NbC<110> field emitters.
Figure 2 shows the shape of the tip of the chip after flash heating at 00°C, Figure 2 shows the emission pattern from the emitter after flash heating at 1800°C, and Figure 3 shows the emission pattern of the field emitter obtained by the method of the present invention. Figure 4 shows the change over time of the total radiation current of the field emitter obtained in the example of the present invention (the degree of vacuum is 1).
10-10 Torr). Patent applicant Nobuo Nagase, Institute of Inorganic Materials, Science and Technology Agency Figure 1 Figure 2 Figure 3 Time (minutes)
Claims (1)
のもとで、エチレンその他の炭化水素系ガスに５０００
Ｌ（１Ｌ＝１×１０＾−＾６Ｔｏｒｒ・秒）以上露出し
、その表面にグラファイト膜を形成させた後、超高真空
下で１０＾８Ｖ／ｃｍ以上の強電界を印加することを特
徴とする高安定電子放射特性を示す炭化ニオブフィール
ドエミッターの作製方法。Niobium carbide single crystal emitter at 1400-1800℃
5,000 to ethylene and other hydrocarbon gases under
L (1L = 1 x 10^-^6 Torr/second) or more, and after forming a graphite film on the surface, a strong electric field of 10^8 V/cm or more is applied under ultra-high vacuum. A method for fabricating a niobium carbide field emitter that exhibits highly stable electron emission characteristics.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16806690A JPH0628130B2 (en) | 1990-06-26 | 1990-06-26 | Method for producing niobium carbide field emitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16806690A JPH0628130B2 (en) | 1990-06-26 | 1990-06-26 | Method for producing niobium carbide field emitter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0461724A true JPH0461724A (en) | 1992-02-27 |
| JPH0628130B2 JPH0628130B2 (en) | 1994-04-13 |
Family
ID=15861203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16806690A Expired - Lifetime JPH0628130B2 (en) | 1990-06-26 | 1990-06-26 | Method for producing niobium carbide field emitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0628130B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009129547A (en) * | 2007-11-20 | 2009-06-11 | Hitachi High-Technologies Corp | Field emission type electron source and electron beam application device using it |
-
1990
- 1990-06-26 JP JP16806690A patent/JPH0628130B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009129547A (en) * | 2007-11-20 | 2009-06-11 | Hitachi High-Technologies Corp | Field emission type electron source and electron beam application device using it |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0628130B2 (en) | 1994-04-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |