JPH0569076B2 - - Google Patents
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- Publication number
- JPH0569076B2 JPH0569076B2 JP8929988A JP8929988A JPH0569076B2 JP H0569076 B2 JPH0569076 B2 JP H0569076B2 JP 8929988 A JP8929988 A JP 8929988A JP 8929988 A JP8929988 A JP 8929988A JP H0569076 B2 JPH0569076 B2 JP H0569076B2
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- laser beam
- laser
- orientation
- stripes
- 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
- 239000013078 crystal Substances 0.000 claims description 39
- 239000000758 substrate Substances 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 24
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 10
- 238000005224 laser annealing Methods 0.000 claims description 9
- 238000009826 distribution Methods 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims 1
- 230000001678 irradiating effect Effects 0.000 claims 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 5
- 238000000137 annealing Methods 0.000 description 5
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000013081 microcrystal Substances 0.000 description 2
- 241000446313 Lamella Species 0.000 description 1
- UMVBXBACMIOFDO-UHFFFAOYSA-N [N].[Si] Chemical compound [N].[Si] UMVBXBACMIOFDO-UHFFFAOYSA-N 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000004518 low pressure chemical vapour deposition Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000004857 zone melting Methods 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、SOI基板の製造にさいして多結晶Si
を単結晶化するための種結晶領域を形成させるレ
ーザアニール方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to the use of polycrystalline silicon in the production of SOI substrates.
This invention relates to a laser annealing method for forming a seed crystal region for single-crystallizing.
（従来の技術）
従来基板の面積に対してSOIの面積の割合が大
きい（SOI面積率の大きい）SOI基板の形成方法
としては、例えば、アプライド・フイジクス・レ
ター（Applied Physics Letters）、第41巻346ペ
ージ（1982年）に記載さている、シリコン窒化膜
による選択反射防止膜法と呼ばれる方法がある。
この方法で、SOI基板の面方位を制御する最も一
般的な方法としては、例えば第33回応用物理学関
係連合講演会講演予稿集527ページ1a−Ｑ−１に
記載されている様に、絶縁膜上に堆積した多結晶
シリコン膜を、基板の一部を種結晶として用いた
横方向の帯域溶融エピタキシヤル成長法で最結晶
化するSOI基板の形成方法があつた。(Prior art) As a conventional method for forming an SOI substrate in which the ratio of the SOI area to the area of the substrate is large (high SOI area ratio), for example, Applied Physics Letters, Vol. 41 There is a method called the selective antireflection coating method using a silicon nitride film, which is described on page 346 (1982).
The most common way to control the plane orientation of an SOI substrate using this method is to There is a method for forming an SOI substrate in which a polycrystalline silicon film deposited on the film is re-crystallized by a lateral zone melting epitaxial growth method using a part of the substrate as a seed crystal.
さらに、レーザアニールで、種結晶を用いずに
基板垂直方向が＜100＞に制御された結晶粒から
なるSOI基板を形成する方法としては、昭和62年
秋季応用物理学会予稿集549ページ30P−Ｂ−77
にあるように多結晶シリコンを２段階でレーザビ
ームアニールする方法があつた。この方法では第
１段階のアニールでSiラメラと呼ばれる基板垂直
方向に＜100＞方位、ストライプに平行な方向に
＜110＞の面内方位を持つ人工的な種結晶を形成
し、そのSiラメラを種結晶として第２段階のアニ
ールで単結晶粒を得る事に特徴がある。 Furthermore, as a method for forming an SOI substrate consisting of crystal grains with the vertical direction of the substrate controlled to <100> by laser annealing without using a seed crystal, there is −77
There was a method of laser beam annealing of polycrystalline silicon in two stages, as shown in . In this method, in the first stage of annealing, an artificial seed crystal called a Si lamella is formed with an in-plane orientation of <100> in the direction perpendicular to the substrate and <110> in a direction parallel to the stripes. The feature is that single crystal grains are obtained as seed crystals in the second stage of annealing.
（発明が解決しようとする問題点）
従来の技術のうち第１の方法は基板の種結晶領
域からSOI層に結晶方位を引きつぐ事が技術的に
困難な上、種結晶領域として余分な面積を確保す
る必要がある等の問題点があり望ましくない。(Problems to be Solved by the Invention) Among the conventional techniques, the first method is technically difficult to carry over the crystal orientation from the seed crystal region of the substrate to the SOI layer, and also requires an extra area as the seed crystal region. This is not desirable as there are problems such as the need to ensure that
また第２の方法では第一段階のアニールで、必
ずしも100％の種結晶が基板垂直方向に＜100＞方
位を持つわけでなく、方位の制御性に劣るといつ
た欠点を有する。 Furthermore, in the second method, 100% of the seed crystals do not necessarily have a <100> orientation in the direction perpendicular to the substrate in the first stage of annealing, and this method has the disadvantage that orientation controllability is poor.
本発明の目的は、このような従来技術の問題点
を解決し、基板を種結晶として用いる事なく、基
板垂直方向が＜100＞方位により高い確率で制御
された人工的種結晶を形成するレーザアニール方
法を得る事にある。 The purpose of the present invention is to solve the problems of the prior art, and to provide a laser that forms an artificial seed crystal in which the vertical direction of the substrate is controlled with high probability by the <100> orientation, without using the substrate as a seed crystal. The purpose is to obtain an annealing method.
（問題点を解決するための手段）
本発明によれば、少なくとも表面に絶縁体層を
備えた基板上に、レーザビームアニールされるべ
き多結晶Siを堆積し、該多結晶Si上にストライプ
状にレーザ光の反射防止膜を形成し、楕円形の強
度分布に持つレーザを楕円形の長軸がストライプ
に垂直になるように照射し、さらにそのレーザー
ビームをストライプと垂直な方法に走査して、基
板垂直方向に＜100＞方位を持ちレーザ光の反射
防止膜下の結晶粒界の間に囲まれた結晶粒を形成
する事を特徴とするレーザアニール方法が得られ
る。(Means for Solving the Problems) According to the present invention, polycrystalline Si to be laser beam annealed is deposited on a substrate having an insulating layer on at least the surface, and a stripe pattern is formed on the polycrystalline Si. A laser beam anti-reflection film is formed on the surface, a laser beam with an elliptical intensity distribution is irradiated with the long axis of the ellipse perpendicular to the stripes, and the laser beam is scanned in a direction perpendicular to the stripes. , a laser annealing method is obtained which is characterized by forming crystal grains having <100> orientation in the direction perpendicular to the substrate and surrounded by grain boundaries under the antireflection film of the laser beam.
（作用）
以下に本発明によつて、従来法に比べて高い制
御確率で基板垂直方向が＜100＞に制御された人
工的種結晶を得る事ができる作用を述べる。(Function) The following is a description of the function of the present invention that allows an artificial seed crystal whose substrate vertical direction is controlled to be <100> to be obtained with a higher control probability than conventional methods.
本発明者が基板垂直方向に＜100＞方位を持つ
人工的な種結晶として用いる事が可能なSiラメラ
の形成メカニズムについて詳細に検討した結果に
よれば、多結晶シリコン中の微小結晶粒のうち基
板垂直方向に＜100＞方位を持つものは他のもの
に比べてレーザ光の反射率がわずかに大きい、従
つて適当なレーザパワーを選べば＜100＞方位を
持つ微小結晶粒のみを残して他のものを溶解する
事が可能である。この＜100＞方位を持つ微小結
晶粒が種結晶となつて溶液が固化したものがSiラ
メラであり、さらにこのSiラメラがいくつか合体
して形成された結晶粒を人工的な種結晶として、
さらに大きな単結晶粒を得るのが従来技術で２番
目にあげた方法である。 According to the results of the inventor's detailed study on the formation mechanism of Si lamellae that can be used as an artificial seed crystal with <100> orientation in the direction perpendicular to the substrate, it was found that among the microcrystalline grains in polycrystalline silicon, Those with a <100> orientation perpendicular to the substrate have a slightly higher reflectance of laser light than others. Therefore, if an appropriate laser power is selected, only microcrystal grains with a <100> orientation can be left behind. It is possible to dissolve other things. These microcrystal grains with <100> orientation serve as seed crystals, and the solution solidifies into Si lamellae.Furthermore, the crystal grains formed by several of these Si lamellae are used as artificial seed crystals.
The second method mentioned in the prior art is to obtain even larger single crystal grains.
この人工的種結晶の形成過程をさらに詳しく調
べると、Siラメラが形成され合体して大きな結晶
粒を成長するためには、レーザ光に照射されてい
る時間が重要なパラメータとなる事が明らかにな
つた。その事を示すのが第２図である。第２図の
横軸は試料のある場所がレーザ光に照射されてい
る時間（レーザ光の滞在時間：レーザビーム径／
走査速度）、縦軸は形成された結晶粒の内基板垂
直方向に＜100＞軸または＜100＞から20°以内の
結晶軸をもつ様に制御されたものの割合を表す。
図から明かな様に、レーザ光の滞在時間が長いほ
ど＜100＞に制御されている確率が高くなつてい
る。 A more detailed study of the formation process of this artificial seed crystal revealed that the time of laser light irradiation is an important parameter in order for Si lamellae to form and coalesce to grow large crystal grains. Summer. Figure 2 shows this. The horizontal axis in Figure 2 is the time during which the sample location is irradiated with the laser beam (laser beam residence time: laser beam diameter/
(scanning speed), and the vertical axis represents the proportion of crystal grains that are controlled to have a <100> axis or a crystal axis within 20° from <100> in the direction perpendicular to the substrate.
As is clear from the figure, the longer the residence time of the laser beam, the higher the probability that it is controlled to <100>.
レーザ光の滞在時間を長くする簡単な方法とし
ては、レーザ光の走査速度を遅くする、レー
ザのビーム径を大きくする、の２つの方法が考え
られるが、の方法ではレーザアニールに要する
時間が長くなる上、下層基板にダメージを与える
可能性があり好ましくない。の方法では、レー
ザビーム系を広くすると走査方向に垂直な（スト
ライプに平行な）方向の溶融面積も広がる。その
結果種結晶領域が広くなり、種結晶領域は他の領
域に比べて表面形状が劣る事が予想され好ましく
ない。また、一般にレーザビーム系を広げるとレ
ーザ光の強度分布の不均一性が目立ち、走査方向
に垂直な方向での不均一性はその方向にいくつか
形成された結晶粒それぞれのレーザパワー条件が
異なり、信頼性のある方位制御を妨げる。 There are two easy ways to increase the residence time of the laser beam: slow down the scanning speed of the laser beam and increase the laser beam diameter, but method 2 takes a long time for laser annealing. Moreover, this is not preferable because it may damage the underlying substrate. In this method, when the laser beam system is widened, the melted area in the direction perpendicular to the scanning direction (parallel to the stripes) also increases. As a result, the seed crystal region becomes wider, and the surface shape of the seed crystal region is expected to be inferior to that of other regions, which is not preferable. Additionally, in general, when the laser beam system is widened, non-uniformity in the intensity distribution of the laser light becomes noticeable, and non-uniformity in the direction perpendicular to the scanning direction is caused by different laser power conditions for each of the crystal grains formed in that direction. , preventing reliable azimuth control.
そこで本発明によれば、楕円形の強度分布を持
つレーザを楕円の長軸方向に走査する事によつ
て、走査方向のレーザ径のみ広がりレーザ光の滞
在時間が長くなつて＜100＞の制御確率が向上す
る。また走査方向に平行な方向には楕円の短軸が
レーザ径となるため、種結晶領域は狭くてよくレ
ーザ光強度の不均一性も影響が小さい。 Therefore, according to the present invention, by scanning a laser having an elliptical intensity distribution in the long axis direction of the ellipse, only the laser diameter in the scanning direction is expanded and the residence time of the laser beam is lengthened, resulting in <100> control. Probability improves. In addition, since the short axis of the ellipse is the laser diameter in the direction parallel to the scanning direction, the seed crystal region can be narrow and the non-uniformity of laser light intensity has little effect.
（実施例）
以下本発明の実施例について図面を参照して詳
細に説明する。(Example) Examples of the present invention will be described in detail below with reference to the drawings.
第１図は、本発明の実施例を説明するための斜
視図である。試料はSi基板１０にSiO2２０を
CVD法で膜厚1μｍ堆積し、その上に基板温度700
℃のLPCVD法で多結晶Si３０を0.5μｍ堆積した。
この多結晶Siは700℃程度の通常より高い温度で
堆積しているので、堆積直後の状態で基板垂直方
向に＜100＞方位を持つ結晶粒が他のものに比べ
て20倍以上の割合で存在し、強い＜100＞配向性
を持ち、Siラメラの形成に有利である。さらに厚
さ0.06μｍの窒素シリコン４０を堆積し、ピツチ
を15μｍ、ストライプ幅を5μｍのストライプ状に
通常にフオトリソグラフイー技術で形成した。こ
の試料に、シリンドリカルレンズで長軸：短軸＝
３：１比に成形したレーザ光を長軸が窒化シリコ
ンのストライプに垂直になる様に照射し、ストラ
イプに垂直な方向に走査した。その際のレーザ径
は長軸の長さで50〜250μｍ、レーザパワーは５
〜20W、基板温度は300〜700℃、走査速度は0.1
〜３mm／secであつた。また比較のために、通常
の円形の強度分布をもつレーザ径30〜120μｍの
レーザ光で同様のレーザアニールを行つた。 FIG. 1 is a perspective view for explaining an embodiment of the present invention. The sample is SiO 2 20 on a Si substrate 10.
A film with a thickness of 1 μm is deposited using the CVD method, and a substrate temperature of 700
Polycrystalline Si30 was deposited to a thickness of 0.5 μm using the LPCVD method at ℃.
Since this polycrystalline Si is deposited at a temperature higher than normal, around 700°C, the proportion of crystal grains with <100> orientation perpendicular to the substrate is more than 20 times that of other grains immediately after deposition. It has a strong <100> orientation and is advantageous for the formation of Si lamellae. Further, nitrogen silicon 40 was deposited to a thickness of 0.06 μm, and formed into stripes with a pitch of 15 μm and a stripe width of 5 μm using a conventional photolithography technique. On this sample, a cylindrical lens is applied to the long axis: short axis =
A laser beam shaped at a ratio of 3:1 was irradiated with the long axis perpendicular to the silicon nitride stripes, and scanned in a direction perpendicular to the stripes. The laser diameter at this time is 50 to 250 μm in terms of the long axis length, and the laser power is 5
~20W, substrate temperature 300~700℃, scan speed 0.1
It was ~3 mm/sec. For comparison, similar laser annealing was performed using a laser beam with a laser diameter of 30 to 120 μm and a normal circular intensity distribution.
こうして得た人工的種結晶の結晶性の評価を選
択エツチ法で、面方位の観察をECP法で評価し
た。その結果、それぞれの条件で形成された全結
晶粒のうち基板垂直方向に＜100＞あるいは＜100
＞から20°以内の結晶軸を持つものの割合は、同
じ溶融幅、走査速度の比較ではいずれの場合も楕
円形のレーザを用いた方が高い。また、円形の強
度分布を持つレーザでは最高でも78％の結晶粒し
か所望の方位に制御できないのに対して、楕円の
レーザを用いると最高97％の結晶粒が方位制御さ
れる事が確認された。 The crystallinity of the artificial seed crystal thus obtained was evaluated using the selective etching method, and the plane orientation was observed using the ECP method. As a result, out of all the crystal grains formed under each condition, <100> or <100>
The proportion of crystals with crystal axes within 20° from In addition, it was confirmed that a laser with a circular intensity distribution can control the orientation of only 78% of the crystal grains at the desired direction, whereas when an elliptical laser is used, the orientation of up to 97% of the crystal grains can be controlled. Ta.
本実施例ではSi基板を用いたがサフアイア基板
等他の基板を用いても同様な効果が得られる。ま
た、窒化シリコンの間隔、幅も本実施例に限定さ
れたものではない。さらに本実施例では、反射防
止膜として窒化シリコンを用いたが他の構造（例
えば、SiO2／Si3N4）で反射防止膜を形成しても
同様の効果が得られる。 Although a Si substrate is used in this embodiment, similar effects can be obtained by using other substrates such as a sapphire substrate. Furthermore, the spacing and width of silicon nitride are not limited to those in this embodiment. Furthermore, although silicon nitride is used as the antireflection film in this embodiment, the same effect can be obtained by forming the antireflection film with another structure (for example, SiO 2 /Si 3 N 4 ).
（発明の効果）
本発明によれば、多結晶中の微小結晶粒のレー
ザ光の反射率についての面方位依存性を有効に利
用できるので基板を種結晶として用いる事なく、
基板垂直方向が＜100＞方位により高い確率で制
御された人工的種結晶を形成するレーザアニール
方法が得られる。(Effects of the Invention) According to the present invention, it is possible to effectively utilize the surface orientation dependence of the laser beam reflectance of microcrystalline grains in polycrystals, without using the substrate as a seed crystal.
A laser annealing method can be obtained that forms an artificial seed crystal whose orientation perpendicular to the substrate is controlled with a high probability by the <100> orientation.
第１図は本発明の実施例を説明するための斜視
図、第２図はレーザ光の滞在時間と＜100＞方位
への制御確率の関係を示す図である。
１０……Si基板、２０……SiO2、３０……多
結晶Si、４０……窒化シリコン。
FIG. 1 is a perspective view for explaining an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the residence time of a laser beam and the control probability toward the <100> direction. 10...Si substrate, 20... SiO2 , 30...polycrystalline Si, 40...silicon nitride.
Claims (1)
多結晶Siとストライプ状のレーザ光反射防止膜が
順次形成されてある基板をレーザアニールするこ
とにより多結晶Siを再結晶化させるレーザアニー
ル方法において、楕円形の強度分布を持つレーザ
光を楕円の長軸がストライプに垂直になるように
照射し、さらにそのレーザビームをストライプと
垂直な方向に走査することにより、反射防止膜下
の結晶粒界に囲まれた領域に基板垂直方向に＜
100＞方位を持つ結晶粒を形成する工程を含む事
を特徴とするレーザアニール方法。1. In a laser annealing method in which polycrystalline Si is recrystallized by laser annealing a substrate in which polycrystalline Si and a striped laser beam antireflection film are sequentially formed on a substrate having an insulating layer on at least the surface. By irradiating a laser beam with an elliptical intensity distribution so that the long axis of the ellipse is perpendicular to the stripes, and then scanning the laser beam in a direction perpendicular to the stripes, the crystal grain boundaries under the antireflection coating are In the area surrounded by <
A laser annealing method characterized by including a step of forming crystal grains with a 100> orientation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8929988A JPH01261291A (en) | 1988-04-13 | 1988-04-13 | Laser annealing process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8929988A JPH01261291A (en) | 1988-04-13 | 1988-04-13 | Laser annealing process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01261291A JPH01261291A (en) | 1989-10-18 |
| JPH0569076B2 true JPH0569076B2 (en) | 1993-09-30 |
Family
ID=13966793
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8929988A Granted JPH01261291A (en) | 1988-04-13 | 1988-04-13 | Laser annealing process |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01261291A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5077235A (en) * | 1989-01-24 | 1991-12-31 | Ricoh Comany, Ltd. | Method of manufacturing a semiconductor integrated circuit device having SOI structure |
| JP2003168645A (en) * | 2001-12-03 | 2003-06-13 | Hitachi Ltd | Semiconductor thin film device, its manufacturing method, and image display device |
| JP2004087535A (en) * | 2002-08-22 | 2004-03-18 | Sony Corp | Method for manufacturing crystalline semiconductor material and method for manufacturing semiconductor device |
-
1988
- 1988-04-13 JP JP8929988A patent/JPH01261291A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01261291A (en) | 1989-10-18 |
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