JPH0352435B2 - - Google Patents
Info
- Publication number
- JPH0352435B2 JPH0352435B2 JP11355487A JP11355487A JPH0352435B2 JP H0352435 B2 JPH0352435 B2 JP H0352435B2 JP 11355487 A JP11355487 A JP 11355487A JP 11355487 A JP11355487 A JP 11355487A JP H0352435 B2 JPH0352435 B2 JP H0352435B2
- Authority
- JP
- Japan
- Prior art keywords
- molecular beam
- beam source
- crucible
- source cell
- mbe
- 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
Links
- 239000000758 substrate Substances 0.000 claims description 19
- 238000001451 molecular beam epitaxy Methods 0.000 description 19
- 239000000463 material Substances 0.000 description 15
- 230000007547 defect Effects 0.000 description 12
- 239000013078 crystal Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 239000004065 semiconductor Substances 0.000 description 6
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000407 epitaxy Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Physical Deposition Of Substances That Are Components Of Semiconductor Devices (AREA)
Description
【発明の詳細な説明】
［概要］
分子線エピタキシヤル成長装置に配置する分子
線源セルを、筒状の主るつぼ（坩堝）の開口部
に、ヒータを内蔵した逆円錐状のガイド筒を付設
した構造にする。[Detailed Description of the Invention] [Summary] A molecular beam source cell placed in a molecular beam epitaxial growth apparatus is attached to an inverted conical guide tube with a built-in heater at the opening of a cylindrical main crucible. structure.
そうすれば、成長層の表面欠陥が減少して、且
つ、安定に結晶層が成長できる。 By doing so, surface defects in the growth layer are reduced and the crystal layer can be grown stably.
［産業上の利用分野］
本発明は分子線エピタキシヤル成長装置に係
り、特に分子線源を蓄えたセル（容器）の構造に
関する。[Industrial Field of Application] The present invention relates to a molecular beam epitaxial growth apparatus, and particularly to the structure of a cell (container) storing a molecular beam source.
周知のように、半導体装置を製造する際、結晶
基板に沿つて半導体膜をエピタキシヤル成長する
エピタキシー法が知られており、これは半導体製
造の最も基礎的な技術である。 As is well known, when manufacturing a semiconductor device, an epitaxy method is known in which a semiconductor film is epitaxially grown along a crystal substrate, and this is the most basic technology for semiconductor manufacturing.
このようなエピタキシー法において、最近、分
子線エピタキシー（MBE；Molecular Beam
Epitaxy）法が開発されており、この分子線エピ
タキシー法は高真空下（10-9Torr以下）で成長
する方法で、清浄な結晶基板面が維持できるため
に、低温度でのエピタキシヤル成長が可能で、且
つ、膜厚を数10Å程度の単原子レベルで精密な制
御ができるという特徴のある方法である。 Recently, molecular beam epitaxy (MBE) has been used in such epitaxy methods.
This molecular beam epitaxy method is a method of growing under high vacuum (below 10 -9 Torr), and because it maintains a clean crystal substrate surface, epitaxial growth at low temperatures is possible. This method is unique in that it is possible to precisely control the film thickness at the monatomic level of several tens of angstroms.
更に、MBE法は、各種元素あるいは化合物元
素のヘテロ接合が容易に得られるという利点があ
り、GaAsなどの化合物半導体デバイスの急峻な
接合構造の形成に最適な方法とされている。 Furthermore, the MBE method has the advantage that heterojunctions of various elements or compound elements can be easily obtained, and is considered to be an optimal method for forming steep junction structures in compound semiconductor devices such as GaAs.
このように利点の多いMBE法ではあるが、成
長速度の不安定性や表面欠陥が生じ易い問題があ
り、その対策が強く望まれている。 Although the MBE method has many advantages as described above, there are problems in that the growth rate is unstable and surface defects are easily generated, and countermeasures for these problems are strongly desired.
［従来の技術と発明が解決しようとする問題点］
第２図は分子線エピタキシヤル成長（MBE）
装置全体の要部概要図を示しており、１は高真空
処理容器、２は被成長基板（ウエハー）、３は分
子線源セル、４は冷却隔壁（液体窒素シユラウ
ド）、５はシヤツター、６は真空排気口である。[Prior art and problems to be solved by the invention] Figure 2 shows molecular beam epitaxial growth (MBE).
The diagram shows a schematic diagram of the main parts of the entire apparatus. 1 is a high vacuum processing container, 2 is a growth substrate (wafer), 3 is a molecular beam source cell, 4 is a cooling partition (liquid nitrogen shroud), 5 is a shutter, and 6 is a is the vacuum exhaust port.
このようなMBE装置を用いて、被成長基板２
に分子線エピタキシヤル成長を行なう場合、所望
の分子線源を蓄えた分子線源セル３の上のシヤツ
ター５を開けて、加熱ヒータで溶融させた分子線
源から分子線を放射させ、被成長基板上にエピタ
キシヤル成長させる。図のように、一つの被成長
基板２に対して多数のセルが設けられているが、
それは例えば、GaAs基板に対して種々の組成の
結晶層を成長し、更に、複数の結晶層を接合して
次々に成長するためで、それにはシヤツターの開
閉によつて切り換えがおこなわれる。 Using such an MBE apparatus, the growth substrate 2
When performing molecular beam epitaxial growth, the shutter 5 above the molecular beam source cell 3 storing the desired molecular beam source is opened, and the molecular beam is emitted from the molecular beam source melted by a heater. Epitaxially grown on the substrate. As shown in the figure, a large number of cells are provided for one growth substrate 2.
For example, this is because crystal layers of various compositions are grown on a GaAs substrate, and then a plurality of crystal layers are bonded and grown one after another, and switching is performed by opening and closing a shutter.
このようなMBE装置のうちの、分子線源セル
の断面図を第３図に示しており、通常、分子線源
セルは焼結窒化硼素（PBN）材からなるホーン
状（角状）のるつぼ（クルーシブル；crucible）
１１と、るつぼの周囲に配置したカンタル巻線の
ヒータ１２とで構成され、るつぼ内の分子線源
（ソース材料）を加熱溶融し気化させて分子線を
発生している。なお、Ｓはソース材料の任意の表
面位置を示し、Ｔは温度測定用の熱電対である。 A cross-sectional view of the molecular beam source cell in such an MBE device is shown in Figure 3, and the molecular beam source cell is usually a horn-shaped crucible made of sintered boron nitride (PBN) material. (crucible)
11 and a Kanthal-wound heater 12 arranged around the crucible, the molecular beam source (source material) in the crucible is heated and melted and vaporized to generate molecular beams. Note that S indicates an arbitrary surface position of the source material, and T is a thermocouple for temperature measurement.
また、第４図はMBE装置における分子線源セ
ルと被成長基板との相対位置を図示している。図
のように、分子線源セルの中心は被成長基板の中
心に向つており、この位置関係によつて被成長基
板面に成長する膜厚の均一な領域の直径Ｄが決定
される。すなわち、直径Ｄは
Ｄ＝ｋ（Ａ＋2Ltanθ0）／cosθ
なる関係式で表わされ（特開昭59−211225号参
照）、ここに
ｋ；比例定数，Ｌ；セルと基板との距離，
θ；分子線中心と基板との角度，
Ａ；セルの開口径，θ0；セルの開口角
であるが、従来よりこの式を参照して、MBE装
置の設計がおこなわれている。 Moreover, FIG. 4 illustrates the relative positions of the molecular beam source cell and the growth target substrate in the MBE apparatus. As shown in the figure, the center of the molecular beam source cell is directed toward the center of the growth substrate, and this positional relationship determines the diameter D of a region with a uniform thickness grown on the growth substrate surface. That is, the diameter D is expressed by the relational expression D=k(A+2Ltanθ 0 )/cosθ (see JP-A-59-211225), where k: proportionality constant, L: distance between cell and substrate, θ; The angle between the center of the molecular beam and the substrate, A: aperture diameter of the cell, θ 0 : aperture angle of the cell. Conventionally, MBE apparatuses have been designed with reference to this formula.
且つ、この式から、分子線源セルの形状によつ
て成長膜厚の均一な領域が変化することが明らか
である。また、この式を解析すると、直径Ｄを大
きくするためにはθ0を大きくする必要があり、そ
のθ0を大きくすれば、るつぼ内のソース材料の消
費によつてソース材料の表面積の変動が大きくな
り、従つて、分子線の量、すなわち、成長速度が
大きく変化すると云う欠点があることが判る。 Moreover, from this equation, it is clear that the region where the grown film thickness is uniform changes depending on the shape of the molecular beam source cell. Also, analyzing this equation shows that in order to increase the diameter D, it is necessary to increase θ 0 , and by increasing θ 0 , the variation in the surface area of the source material due to the consumption of the source material in the crucible is reduced. It can be seen that there is a drawback that the amount of molecular beam, that is, the growth rate changes greatly.
一方、MBE装置によつて成長した結晶層には
MBE特有の表面欠陥が生じ、それは分子線源セ
ルからソースのスピツテング（spitting；吐くこ
と）とソース材料の酸化とが原因とされている。
そのうち、ソース材料の酸化はソースの脱ガスを
十分に行なえば回避できるが、スピツテイングの
方は従来の分子線源セルの形状では回避すること
が難しい。このソースのスピツテングの原因は分
子線源セル開口部の温度が低下するため、ソース
が開口部に付着して、それが塊状になつて被成長
基板に到達するからである。このようにして生じ
た基板の欠陥をオーバルデイフエクト（oval
defect；卵形の欠陥）と云つて、半導体装置の性
能劣化に深い関わりがある。 On the other hand, the crystal layer grown by MBE equipment has
Surface defects characteristic of MBE occur and are caused by spitting of the source from the molecular beam source cell and oxidation of the source material.
Of these, oxidation of the source material can be avoided by sufficiently degassing the source, but spitting is difficult to avoid with conventional molecular beam source cell shapes. The cause of this source spitting is that the temperature of the opening of the molecular beam source cell decreases, so that the source adheres to the opening, forms a lump, and reaches the growth substrate. The defects on the board that occur in this way are called oval defects (oval defects).
Defects (oval-shaped defects) are closely related to performance deterioration of semiconductor devices.
本発明はこのような表面欠陥や成長速度の変動
を減少させるための分子線源セルを備えたMBE
装置を提案するものである。 The present invention proposes an MBE equipped with a molecular beam source cell to reduce such surface defects and growth rate fluctuations.
This paper proposes a device.
［問題点を解決するための手段］
その目的は、筒状の主るつぼの開口部に、ヒー
タを内蔵した逆円錐状のガイド筒を設け、該開口
部が被成長基板に対向している分子線源セルを備
えたMBE装置によつて達成される。[Means for solving the problem] The purpose is to provide an inverted conical guide tube with a built-in heater in the opening of a cylindrical main crucible, and to This is accomplished by an MBE device equipped with a source cell.
［作用］
即ち、本発明にかかるMBE装置には、筒状の
主るつぼ（メインるつぼ）と、その開口部に、ヒ
ータを内蔵した逆円錐状（漏斗状）のガイド筒を
付設した分子線源セルを設ける。[Operation] That is, the MBE apparatus according to the present invention includes a molecular beam source that includes a cylindrical main crucible and an inverted conical (funnel-shaped) guide tube with a built-in heater attached to the opening of the main crucible. Set up a cell.
そうすれば、成長層の表面欠陥が減少し、且
つ、安定に成長速度も安定する。 By doing so, surface defects in the grown layer are reduced and the growth rate is also stably stabilized.
［実施例］
以下、図面を参照して実施例によつて詳細に説
明する。[Examples] Hereinafter, examples will be described in detail with reference to the drawings.
第１図は本発明にかかるMBE装置の分子線源
セルの断面図を示しており、２０はソース材料を
収容する主るつぼ、２１はヒータを内蔵した逆円
錐状のガイド筒，２２はタンタル巻線からなるヒ
ータ、T1，T2は温度測定用の熱電対である。同
図において、主るつぼ２０は従来のホーン状るつ
ぼ１１に相当し、本例では形状を円筒形にしてい
るが、このような形状にすると、主るつぼ２０内
部のソース材料が消耗してソース材料の表面Ｓの
位置が下つても、その表面積が変化しない。そう
すると、分子線の放射量が変化せず、成長速度が
一定になる利点がある。なお、この主るつぼ２０
は円筒形に限るものではなく、上記のようにソー
ス材料の消費に応じて表面積が変化しない筒状に
すれば、他の断面形状でもよい。 FIG. 1 shows a cross-sectional view of the molecular beam source cell of the MBE apparatus according to the present invention, in which 20 is a main crucible containing the source material, 21 is an inverted conical guide tube with a built-in heater, and 22 is a tantalum-wound The heater consists of wires, and T 1 and T 2 are thermocouples for temperature measurement. In the same figure, the main crucible 20 corresponds to the conventional horn-shaped crucible 11, and in this example, the shape is cylindrical. However, if this shape is adopted, the source material inside the main crucible 20 is consumed and the source material Even if the position of the surface S of is lowered, its surface area does not change. This has the advantage that the amount of molecular beam radiation does not change and the growth rate remains constant. Furthermore, this main crucible 20
is not limited to a cylindrical shape, but may have any other cross-sectional shape as long as it is a cylindrical shape whose surface area does not change depending on the consumption of the source material as described above.
また、ガイド筒２１は逆円錐筒の形状を有し、
主るつぼ２０の開口部に嵌め込むように構成し
て、その開口が被成長基板に対向した位置（第４
図参考）にする。且つ、このガイド筒２１は主る
つぼ２０と同様にPBNで作製し、中央にカーボ
ンからなるヒータ２１Ｈを挟んだサンドイツチ構
造にして、全体をヒータで加熱する。 Further, the guide tube 21 has the shape of an inverted conical tube,
The structure is configured to fit into the opening of the main crucible 20, and the opening faces the growth substrate (the fourth
(see figure). In addition, this guide cylinder 21 is made of PBN similarly to the main crucible 20, and has a sandwich structure with a heater 21H made of carbon sandwiched in the center, and the whole is heated by the heater.
かくして、主るつぼ２０の中のソース材料をヒ
ータ２２で加熱溶融し、熱電対T1で温度を監視
しながら制御し、これによつて、放射する分子線
の量がコントロールされる。一方、ガイド筒２１
はヒータ２１Ｈで加熱して、その温度を熱電対
T2で監視して制御し、これによつて開口部の冷
却を防止する。 Thus, the source material in the main crucible 20 is heated and melted by the heater 22, and the temperature is monitored and controlled by the thermocouple T1 , thereby controlling the amount of molecular beams emitted. On the other hand, the guide tube 21
is heated with heater 21H, and the temperature is measured with a thermocouple.
T 2 is monitored and controlled, thereby preventing cooling of the opening.
このような分子線源セルの構造にして、これを
MBE装置に設置すれば、主るつぼ内のソース材
料が消費しても、その表面積の変化がなくなり、
分子線の放射量が変化せずに一定し、且つ、開口
部のガイド筒２１が加熱されるため、ソースが開
口部に付着して、それが塊状となつて被成長基板
に到達するスピツテングの問題も解消する。従つ
て、結晶層の成長速度が安定し、被成長基板の表
面欠陥が低減する大きな効果がある。 With the structure of a molecular beam source cell like this,
When installed in an MBE device, even if the source material in the main crucible is consumed, its surface area will not change.
Since the amount of radiation of the molecular beam remains unchanged and the guide cylinder 21 at the opening is heated, the source adheres to the opening and forms a lump that reaches the growth substrate. It also solves the problem. Therefore, there is a great effect that the growth rate of the crystal layer is stabilized and surface defects of the growth substrate are reduced.
なお、実験結果によれば、GaAs層を成長する
ために、ソース材料のGaを収容した分子線源セ
ルにおいて、熱電対T1で測定した主るつぼの温
度を1000℃とし、熱電対T2で測つた副るつぼの
温度を1100℃にしてGaAs層を成長したところ、
その表面欠陥は10分の１に減少し、また、分子線
の安定性も極めて向上した。 According to the experimental results, in order to grow a GaAs layer, in a molecular beam source cell containing Ga as the source material, the temperature of the main crucible measured with thermocouple T 1 was set to 1000°C, and the temperature of the main crucible measured with thermocouple T 2 was set to 1000°C. When the GaAs layer was grown with the temperature of the sub-crucible measured at 1100℃,
The surface defects were reduced to one-tenth, and the stability of the molecular beam was also greatly improved.
また、このような分子線源セルにすれば、主る
つぼの形状の自由度が大きくなり、一層大きな容
量のるつぼを用いてソース材料を増やし、長時間
使用できるようにすることもできる。 Moreover, if such a molecular beam source cell is used, the degree of freedom in the shape of the main crucible is increased, and a larger capacity crucible can be used to increase the amount of source material, making it possible to use the cell for a long time.
従つて、本発明にかかるMBE装置を用れば、
高品質な結晶層が成長できるものである。 Therefore, if the MBE device according to the present invention is used,
A high quality crystal layer can be grown.
［発明の効果］
以上の説明から明らかなように、本発明にかか
る分子線源セルを具備した分子線エピタキシヤル
成長装置によれば、成長結晶層の品質が顕著に改
善されて、半導体装置を高性能化することができ
る。[Effects of the Invention] As is clear from the above description, according to the molecular beam epitaxial growth apparatus equipped with the molecular beam source cell according to the present invention, the quality of the grown crystal layer is significantly improved, and semiconductor devices can be grown. High performance can be achieved.
第１図は本発明にかかるMBE装置の分子線源
セルの断面図、第２図はMBE装置の全体概要図、
第３図は従来の分子線源セルの断面図、第４図は
被成長基板と分子線源セルとの相対位置を示す図
である。
図において、１は高真空処理容器、２は被成長
基板（ウエハー）、３は分子線源セル、１１はる
つぼ、１２，２２はヒータ、２０は主るつぼ、２
１はガイド筒、２１Ｈはガイド筒のヒータ、Ｔ，
T1，T2は熱電対を示している。
FIG. 1 is a sectional view of the molecular beam source cell of the MBE device according to the present invention, FIG. 2 is an overall schematic diagram of the MBE device,
FIG. 3 is a sectional view of a conventional molecular beam source cell, and FIG. 4 is a diagram showing the relative positions of the growth substrate and the molecular beam source cell. In the figure, 1 is a high vacuum processing container, 2 is a growth substrate (wafer), 3 is a molecular beam source cell, 11 is a crucible, 12 and 22 are heaters, 20 is a main crucible, 2
1 is the guide cylinder, 21H is the heater of the guide cylinder, T,
T 1 and T 2 indicate thermocouples.
Claims (1)
た逆円錐状のガイド筒を設け、該開口部が被成長
基板に対向している分子線源セルを備えているこ
とを特徴とする分子線エピタキシヤル成長装置。1. A molecule characterized in that an inverted conical guide tube with a built-in heater is provided at the opening of a cylindrical main crucible, and the opening is equipped with a molecular beam source cell facing a growth substrate. Line epitaxial growth equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11355487A JPS63282189A (en) | 1987-05-12 | 1987-05-12 | Molecular beam epitaxial growth device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11355487A JPS63282189A (en) | 1987-05-12 | 1987-05-12 | Molecular beam epitaxial growth device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63282189A JPS63282189A (en) | 1988-11-18 |
| JPH0352435B2 true JPH0352435B2 (en) | 1991-08-09 |
Family
ID=14615235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11355487A Granted JPS63282189A (en) | 1987-05-12 | 1987-05-12 | Molecular beam epitaxial growth device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63282189A (en) |
-
1987
- 1987-05-12 JP JP11355487A patent/JPS63282189A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63282189A (en) | 1988-11-18 |
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