JPH0511412B2 - - Google Patents
Info
- Publication number
- JPH0511412B2 JPH0511412B2 JP24996185A JP24996185A JPH0511412B2 JP H0511412 B2 JPH0511412 B2 JP H0511412B2 JP 24996185 A JP24996185 A JP 24996185A JP 24996185 A JP24996185 A JP 24996185A JP H0511412 B2 JPH0511412 B2 JP H0511412B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- cosi
- substrate
- phase epitaxial
- single crystal
- 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.)
- Expired - Lifetime
Links
- 239000000758 substrate Substances 0.000 claims description 30
- 229910019001 CoSi Inorganic materials 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 19
- 239000013078 crystal Substances 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 239000007790 solid phase Substances 0.000 description 19
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000009792 diffusion process Methods 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 3
- 238000000137 annealing Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000007665 sagging Methods 0.000 description 2
- 229910020711 Co—Si Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000002003 electron diffraction Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 238000001004 secondary ion mass spectrometry Methods 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Electrodes Of Semiconductors (AREA)
- Physical Deposition Of Substances That Are Components Of Semiconductor Devices (AREA)
- Recrystallisation Techniques (AREA)
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明はCoSi2膜の形成方法に関する。特に良
質の結晶性を有するCoSi2単結晶膜を容易に形成
でき、同時に、Si基板中へCoSi2からの不純物の
拡散の影響が少ないという、半導体素子に好適な
CoSi2膜の固相エピタキシヤル成長法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for forming a CoSi 2 film. It is suitable for semiconductor devices because it can easily form CoSi 2 single-crystal films with particularly good crystallinity, and at the same time there is little influence of impurity diffusion from CoSi 2 into the Si substrate.
Concerning solid-phase epitaxial growth of CoSi 2 films.
従来、Si単結晶の上にCoSi2単結晶膜をエピタ
キシヤル成長する方法として、Co膜とSi膜板と
を反応させる固相エピタキシヤル法、たとえばア
ール・テイー・トウング等によるアプライド・フ
イジツクス・レターズ、第40巻、第684ページ、
1982年刊（R.T.Tung et al.、Appl.Phys.Lett.、
40（1982）、p.684）の論文記載の方法が知られて
いた。固相エピタシヤル法は形成法が容易である
が、反応が拡散を伴つたものであり、Si中にCo
が拡散したり、膜の表面のモルホロジー
（morphology）が悪いという欠点を有した。
Conventionally, as a method for epitaxially growing a CoSi 2 single crystal film on a Si single crystal, a solid phase epitaxial method in which a Co film and a Si film plate are reacted, for example, Applied Physics Letters by R.T. Toung et al. , Volume 40, Page 684,
Published in 1982 (RTTung et al., Appl.Phys.Lett.,
40 (1982), p. 684) was known. Although the solid phase epitaxial method is easy to form, the reaction involves diffusion, and Co
However, it has the drawbacks that the membrane is diffused and the morphology of the membrane surface is poor.
本発明の目的は、CoSi2膜の形成方法におい
て、従来の固相エピタキシヤル法並みの容易さ
で、Si基板への影響を少くするような、固相エピ
タキシヤル法を提供することにある。
An object of the present invention is to provide a solid phase epitaxial method for forming a CoSi 2 film that is as easy as the conventional solid phase epitaxial method and has less influence on the Si substrate.
従来の固相エピタキシヤル法の欠点は、下地の
Si基板との反応により核形成による膜の成長が生
じたり、またSiとCoの拡散反応が必須であるた
め、Si基板中にCo原子が不純物として固溶され
てしまうということであつた。したがつて、Si基
板と固相反応を生じさせないようにし、エピタキ
シヤル成長は下地のSi基板に従うようにしてやれ
ば、上記の固相エピタキシヤル法の欠点は解消さ
れる。そのためにSi基板上に下地との反応が生じ
にくい450℃以下の基板温度、望ましくは25〜300
℃にて、CoSi2の組成比になるようにSiとCoの多
層膜を形成する。組成比がCoSi2からずれている
場合は、450℃以上、特に550℃以上の基板温度で
は、下地のSi基板と上に形成した膜との反応が顕
著になるので望ましくない。多層膜の全体として
組成はSiとの格子のミスマツチが少く、容易にエ
ピタキシヤル成長が生じ、しかも、Siとの共存相
として安定なCoSi2になるようにした。この時Co
とSiとの組成比がSi／Co＞２では、エピタキシ
ヤル成長させた時にCoSi2膜に余分のSiが折出し
た状態になり望ましくない。またSi／Co＜1.8で
はCoSi2膜を形成する際不足のSi原子をおぎなう
ため下地からSi原子が拡散してくるが、それに伴
い、CoSi2膜の表面モルホロジーが悪くなり、望
ましくない。200℃以下で形成したSiとCoの多層
膜は、各層が30〜300Åと非常に薄く、また基板
の単結晶基板に比べ多量の格子欠陥を含むので拡
散しやすく、450℃30分という低温でのアニール
でも下地のSiと反応することなく容易に均一な
CoSi2相となる。このCoSi2を形成するアニール
温度は上述の如くSi基板との反応を防ぐという観
点から、450〜550℃である。なお、この多層膜か
らCoSi2膜を形成する工程は、省略してもよい。
The disadvantage of the conventional solid-phase epitaxial method is that
The reaction with the Si substrate causes film growth due to nucleation, and since a diffusion reaction between Si and Co is essential, Co atoms are dissolved as impurities in the Si substrate. Therefore, the above-mentioned drawbacks of the solid-phase epitaxial method can be overcome by preventing a solid-phase reaction with the Si substrate and allowing epitaxial growth to follow the underlying Si substrate. For this reason, the substrate temperature on the Si substrate is 450℃ or less, preferably 25 to 300℃, so that reaction with the underlying substrate is difficult to occur.
A multilayer film of Si and Co is formed at a temperature of 0.degree. C. to have a composition ratio of CoSi 2 . If the composition ratio deviates from CoSi 2 , the reaction between the underlying Si substrate and the film formed thereon becomes significant at substrate temperatures of 450° C. or higher, particularly 550° C. or higher, which is not desirable. The composition of the multilayer film as a whole is such that there is little lattice mismatch with Si, epitaxial growth occurs easily, and CoSi 2 is stable as a coexisting phase with Si. At this time Co
If the composition ratio of Si/Co>2 is undesirable, excess Si will precipitate into the CoSi 2 film during epitaxial growth. In addition, when Si/Co<1.8, Si atoms diffuse from the base to cover the insufficient Si atoms when forming a CoSi 2 film, but the surface morphology of the CoSi 2 film deteriorates accordingly, which is undesirable. Multilayer films of Si and Co formed at temperatures below 200°C are extremely thin, each layer measuring 30 to 300 Å, and contain more lattice defects than single crystal substrates, making them easier to diffuse. Even during annealing, it can be easily uniformly coated without reacting with the underlying Si.
It becomes CoSi 2 phase. The annealing temperature for forming this CoSi 2 is 450 to 550° C. from the viewpoint of preventing reaction with the Si substrate as described above. Note that the step of forming a CoSi 2 film from this multilayer film may be omitted.
次にCoSi2膜あるいはCo−Si多層膜を、下地Si
単結晶基板に対して、固相エピタキシヤル成長さ
せるため、450℃〜1000℃に基板を加熱した。単
結晶成長は、Si基板表面が洗浄であれば、450℃
でも生じるが、結晶性はあまり良くない。600〜
750℃にて、結晶性も良好で、また、表面の凹凸
も原子層オーダーの非常に平滑な単結晶膜を得る
ことができる。800℃以上、特に900℃に加熱する
と、結晶性は良いが、表面の凹凸が大きくなり、
極端な場合は、CoSi2膜に穴があいて、下地のSi
基板が露出するようになつてしまうことがある。
したがつて、600〜800℃の基板加熱温度が固相エ
ピタキシヤル成長させる最適の温度領域である。 Next, a CoSi 2 film or a Co-Si multilayer film is applied to the underlying Si layer.
In order to perform solid phase epitaxial growth on a single crystal substrate, the substrate was heated to 450°C to 1000°C. For single crystal growth, if the Si substrate surface is cleaned, the temperature is 450℃.
However, the crystallinity is not very good. 600～
At 750°C, a single crystal film with good crystallinity and a very smooth surface with irregularities on the order of atomic layers can be obtained. When heated to 800℃ or higher, especially 900℃, the crystallinity is good, but the surface becomes uneven.
In extreme cases, holes may form in the CoSi 2 film, exposing the underlying Si.
The board may become exposed.
Therefore, a substrate heating temperature of 600 to 800°C is the optimum temperature range for solid phase epitaxial growth.
以下本発明の詳細を実施例により説明する。 The details of the present invention will be explained below with reference to Examples.
実施例 １
Si（111）単結晶基板を分子線成長装置に挿入
し、10-10torr台の超高真空中にて低温サーマル
エツチング法により表面の清浄化を行つた。次に
基板温度を室温に下げ、Si層とCo層を各々172
Å、50Åの周期で４層ずつ交互に形成した。その
後、30分間600℃に基板を上げた。反射電子線回
折により結晶性を判定したところ単結晶パターン
が得られ、下地のSi基板（111）面に対して、同
様に（111）面のエピタキシヤル成長が生じてい
ることが判つた。次にオージエ電子分光により分
析したところ、CoSi2に特有のラインシエープの
SiLVVピークが得られ、CoSi2が生成していること
が判つた。断面を観察したところ、通常の固相エ
ピタキシヤル法の場合とは異なり、第１図ｂに示
すように、下地のSi基板を食つてCoSi2が成長し
ているということはなかつた。なお、第１図ａは
Si基板２上にCo層を形成した状態を示す断面図、
第１図ｂはその固相エピタキシヤル成長後の断面
図である。一方、第２図ａは本発明の方法を用い
たもので、Co層１とSi層３を交互にSi基板２上
に積層した状態を示す。第２図ｂはこの状態で固
相エピタキシヤル成長を施こした状態である。ま
た、表面のモルホロジー（molphology）も、ノ
マルスキー型光学顕微鏡でみても何の構造もみら
れない程、鏡面状態であつた。深さ方向にIMA
分析を行つたところ、第３図に示すように、通常
の固相エピタキシヤル法の場合、ａのように界面
のダレは2000Åであり、一方、本発明の固相エピ
タキシヤル法ｂの場合は、界面のダレは400Å程
度であつた。このダレは、分析のイオンスパツタ
に伴うイオン衝撃によるダレの程度であり、本発
明による方法では、Si基板中へCo原子が拡散す
るのは非常に少いことが明らかである。Example 1 A Si (111) single crystal substrate was inserted into a molecular beam growth apparatus, and the surface was cleaned by low-temperature thermal etching in an ultra-high vacuum of 10 -10 torr. Next, the substrate temperature was lowered to room temperature, and the Si layer and Co layer were each
Four layers were formed alternately with a period of 50 Å and a period of 50 Å. Then, raise the substrate to 600 °C for 30 min. When the crystallinity was determined by backscattered electron diffraction, a single crystal pattern was obtained, and it was found that epitaxial growth of the (111) plane had similarly occurred on the (111) plane of the underlying Si substrate. Next, analysis using Auger electron spectroscopy showed that the line shape characteristic of CoSi 2
A Si LVV peak was obtained, indicating that CoSi 2 was produced. When the cross section was observed, unlike in the case of normal solid-phase epitaxial method, as shown in Figure 1b, CoSi 2 did not grow by eating away at the underlying Si substrate. Furthermore, Figure 1a is
A cross-sectional view showing a state in which a Co layer is formed on a Si substrate 2,
FIG. 1b is a sectional view after the solid phase epitaxial growth. On the other hand, FIG. 2a shows a state in which Co layers 1 and Si layers 3 are alternately laminated on a Si substrate 2 using the method of the present invention. FIG. 2b shows the state in which solid phase epitaxial growth was performed in this state. In addition, the morphology of the surface was so mirror-like that no structure could be seen even when viewed with a Nomarski optical microscope. IMA in depth direction
As a result of the analysis, as shown in Figure 3, in the case of the ordinary solid phase epitaxial method, the sag at the interface was 2000 Å as shown in a , whereas in the case of the solid phase epitaxial method b of the present invention, the sag was 2000 Å. The sag at the interface was about 400 Å. This sagging is the extent of sagging due to ion bombardment associated with ion spatter during analysis, and it is clear that in the method according to the present invention, the diffusion of Co atoms into the Si substrate is extremely small.
以上、本発明によれば、
(1) Si基板からSi原子を食うことなしに、しかも
従来の固相エピタキシヤル法と同程度の容易さ
で、同時蒸着法で得られる膜質と同等のものが
形成できる。
As described above, according to the present invention, (1) film quality equivalent to that obtained by the simultaneous vapor deposition method can be obtained without eating Si atoms from the Si substrate, and with the same ease as the conventional solid-phase epitaxial method; Can be formed.
(2) しかも半導体層へCo原子の拡散が少いとい
う特徴を有している。(2) Moreover, it has the characteristic that there is little diffusion of Co atoms into the semiconductor layer.
半導体に対しCoSi2を使用できるという極めて
大きい効用がある。 CoSi 2 can be used for semiconductors, which has an extremely large effect.
第１図ａ，ｂは従来の固相エピタキシヤル法に
よる成長層の断面図で、ａは基板にCo膜形成後
の断面図、ｂはこれを固相エピタキシヤル成長し
た後の断面図である。第２図ａ，ｂは本発明によ
る固相エピタキシヤル法による成長層の断面図
で、ａはCoSi2膜の多層膜形成後の断面図、ｂは
これを固相エピタキシヤル成長した後の断面図で
ある。第３図は二次イオン質量分析によるCoの
深さ方向分析結果を示す図である。
１……Co膜、２……Si基板、３……Si膜、４
……CoSi2膜。
Figures 1a and 1b are cross-sectional views of layers grown by the conventional solid-phase epitaxial method, where a is a cross-sectional view after forming a Co film on a substrate, and b is a cross-sectional view after this is grown by solid-phase epitaxial growth. . Figures 2a and b are cross-sectional views of layers grown by the solid-phase epitaxial method according to the present invention, where a is a cross-sectional view after forming a multilayer CoSi 2 film, and b is a cross-sectional view after solid-phase epitaxial growth. It is a diagram. FIG. 3 is a diagram showing the results of depth direction analysis of Co by secondary ion mass spectrometry. 1...Co film, 2...Si substrate, 3...Si film, 4
...CoSi 2 film.
Claims (1)
温度で、30〜300Åの厚さで所望の周期にCoおよ
びSi膜を交互に当該積層膜全体の組成比がSi／
Co＝２｛＋０ −0.2になるように積層膜を形成した後、
450〜1000℃に加熱してCoSi2膜を形成すること
により、CoSi2単結晶膜をエピタキシヤル成長さ
せることを特徴とするCoSi2膜の形成方法。 ２ 前記Si膜とCo膜の積層膜をアニールによつ
てCoSi2膜とせしめ、次いでCoSi2単結晶膜をエ
ピタキシヤル成長させるこを特徴とする特許請求
の範囲第１項記載のCoSi2膜の形成方法。[Claims] 1. Co and Si films are alternately deposited on a Si single crystal substrate at a substrate temperature of 450°C or less with a thickness of 30 to 300 Å at a desired period so that the composition ratio of the entire laminated film is Si／
After forming a laminated film so that Co=2{+0 −0.2,
A method for forming a CoSi 2 film, which comprises epitaxially growing a CoSi 2 single crystal film by heating to 450 to 1000°C to form a CoSi 2 film. 2. The CoSi 2 film according to claim 1, wherein the laminated film of the Si film and Co film is annealed to form a CoSi 2 film, and then a CoSi 2 single crystal film is epitaxially grown. Formation method.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24996185A JPS62111420A (en) | 1985-11-09 | 1985-11-09 | Method for forming cosi2 film |
| US07/110,580 US5047111A (en) | 1985-03-16 | 1987-10-16 | Method of forming a metal silicide film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24996185A JPS62111420A (en) | 1985-11-09 | 1985-11-09 | Method for forming cosi2 film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62111420A JPS62111420A (en) | 1987-05-22 |
| JPH0511412B2 true JPH0511412B2 (en) | 1993-02-15 |
Family
ID=17200763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24996185A Granted JPS62111420A (en) | 1985-03-16 | 1985-11-09 | Method for forming cosi2 film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62111420A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004070804A1 (en) * | 2003-02-07 | 2004-08-19 | Nec Corporation | Method for forming nickel silicide film, method for manufacturing semiconductor device, and method for etching nickel silicide |
-
1985
- 1985-11-09 JP JP24996185A patent/JPS62111420A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62111420A (en) | 1987-05-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |