JPH067072B2 - Substrate temperature measurement method - Google Patents
Substrate temperature measurement methodInfo
- Publication number
- JPH067072B2 JPH067072B2 JP19904885A JP19904885A JPH067072B2 JP H067072 B2 JPH067072 B2 JP H067072B2 JP 19904885 A JP19904885 A JP 19904885A JP 19904885 A JP19904885 A JP 19904885A JP H067072 B2 JPH067072 B2 JP H067072B2
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- temperature
- thin film
- refractive index
- measured
- 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 - Fee Related
Links
Description
【発明の詳細な説明】 （イ）産業上の利用分野 この発明は基板温度の測定法に関する。さらに詳しくは
屈折率の温度依存性に基づく基板温度の測定法に関す
る。DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a method for measuring a substrate temperature. More specifically, it relates to a method for measuring a substrate temperature based on the temperature dependence of the refractive index.
（ロ）従来の技術 薄膜の形成法には、例えば電子ビーム蒸着（ＥＢ）法，
イオンクラスタビーム蒸着（ＩＣＢ）法，分子線エピタ
キシー（ＭＢＥ）法，気相成長（ＣＶＤ）法，有機金属
気相成長（ＭＯＣＶＤ）法等がある。(B) Conventional Technology For forming a thin film, for example, electron beam evaporation (EB) method,
There are an ion cluster beam deposition (ICB) method, a molecular beam epitaxy (MBE) method, a vapor phase growth (CVD) method, a metal organic chemical vapor deposition (MOCVD) method and the like.
このうち例えばＭＢＥ法は、成長された半導体薄膜およ
び不純物ドーピングの制御性が優れ、かつ急峻で平坦な
ヘテロ界面が得られる等の利点を有しているため、超高
周波半導体素子あるいは半導体レーザに代表される光エ
レクトロニクス素子の製造方法として注目を集めてい
る。Among them, for example, the MBE method has advantages such as excellent controllability of a grown semiconductor thin film and impurity doping, and a steep and flat hetero interface. It has been attracting attention as a method for manufacturing an optoelectronic device.
このＭＢＥ法においても他の薄膜形成法と同様に被成長
基板の基板温度はＭＢＥ成長の重要なパラメータであ
る。In this MBE method, the substrate temperature of the substrate to be grown is an important parameter for MBE growth, as in other thin film forming methods.
具体的には、上記被成長基板を、 ソルダ・マウント方式〔インジウム（Ｉｎ）などのソ
ルダ（ハンダ）でハンダ装着する方法〕を用いてサセプ
ター（保持具）に装着し、サセプターの背後に設置した
ヒータによりまずサセプターを加熱し、溶融したソルダ
を介して熱伝導により基板を加熱する方法、または ソルダ・フリー方式（ソルダを用いないでピンなどで
機械的にクランプする方法）を用いて基板と同程度の貫
通孔を有するサセプターに装着し、ついでこの貫通孔を
通してヒータからの熱輻射により加熱する方法、 により加熱されるが近年インジウムソルダと基板裏面と
の反応により基板の平坦性が損われ成長後のプロセスが
困難になるソルダ・マウント方式よりもソルダ・フリ
ー方式が多用されている。この基板の温度は熱電対ま
たは赤外線放射温度計（加熱基板から放射される赤外線
のうち特定波長を半導体センサなどで検知しその強度よ
り黒体輻射理論に基づき基板の放射率を考慮した上で温
度に換算する方法）により測定されている。これらの測
温方法により基板温度を測定して制御することによって
薄膜成長が図られており、さらに成長膜の面内均一性を
得るために上記サセプターは薄膜成長中回転させる方法
がとられている。Specifically, the above-mentioned substrate to be grown was mounted on a susceptor (holding tool) using a solder mounting method [a method of soldering with solder such as indium (In)] and placed behind the susceptor. The susceptor is first heated by the heater and then the substrate is heated by heat conduction through the molten solder, or the same as the substrate using the solder-free method (method of mechanically clamping with pins without using solder). It is mounted on a susceptor having a through hole of a certain degree, and then heated by heat radiation from a heater through this through hole. In recent years, the flatness of the substrate is lost due to the reaction between the indium solder and the back surface of the substrate, and after growth The solder-free method is used more often than the solder-mount method, which makes the process of making difficult. The temperature of this substrate is measured by a thermocouple or infrared radiation thermometer (a specific wavelength of infrared rays emitted from the heating substrate is detected by a semiconductor sensor, etc., and the emissivity of the substrate is taken into consideration based on its intensity based on the blackbody radiation theory. It is measured by the method of converting to. Thin film growth is achieved by measuring and controlling the substrate temperature by these temperature measuring methods. Further, in order to obtain in-plane uniformity of the grown film, the susceptor is rotated during thin film growth. .
（ハ）発明が解決しようとする問題点 しかしながら熱電対による測温方法の場合、サセプター
は回転しているので熱電対を基板に接触しておくことは
できない。よって熱電対はサセプターの中心部近傍の空
中におかれる。従って基板自身の温度ではなくてサセプ
ターもしくはサセプター近傍の空間の温度を測定してい
ることになる。また熱電対，サセプターおよび基板との
密着状態が基板設定操作ごとや基板厚みの変動により異
なるので、基板測定温度は密着状態の影響を受けるとい
う問題点があった。(C) Problems to be Solved by the Invention However, in the case of the temperature measurement method using the thermocouple, the susceptor is rotating, so the thermocouple cannot be in contact with the substrate. Therefore, the thermocouple is placed in the air near the center of the susceptor. Therefore, not the temperature of the substrate itself but the temperature of the susceptor or the space near the susceptor is measured. Further, since the contact state with the thermocouple, the susceptor, and the substrate varies depending on the substrate setting operation and the variation of the substrate thickness, there is a problem that the substrate measurement temperature is affected by the contact state.
また赤外線放射温度計による測温方法を用い、かつソル
ダ・フリー方式を適用する場合は、基板表面からの赤外
線だけではなくサセプターの貫通孔を通して背後のヒー
タの赤外線もセンサに検知され、両者の強度関係から結
局ヒータの温度を測定していることになるという問題点
があった。In addition, when the temperature measurement method using an infrared radiation thermometer is used and the solder-free method is applied, not only the infrared rays from the substrate surface but also the infrared rays from the heater behind through the through holes of the susceptor are detected by the sensor, and the intensity of both is detected. Due to the relationship, there is a problem in that the temperature of the heater is eventually measured.
以上特に近年注目されているＭＢＥ法について従来技術
の問題点を挙げたがその他の薄膜形成法においても、測
温方法に同様の問題点があった。As described above, the problems of the prior art have been mentioned with respect to the MBE method, which has been particularly attracting attention in recent years, but other thin film forming methods also have the same problems with the temperature measuring method.
この発明は、屈折率が温度依存性を有するという原理を
利用することに着目しなされたものである。ことにエリ
プソメトリーにより各種基板の屈折率を効率良くかつ直
接的に測定できる点並びにかかる方法で測定された屈折
率と基板温度とが、実用領域において優れた直線関係を
有する事実に基づきなされたものである。そしてこの発
明の方法によれば基板の温度を正確に測定することがで
きる。The present invention has been made paying attention to the use of the principle that the refractive index has temperature dependence. In particular, it was made based on the fact that the refractive index of various substrates can be measured efficiently and directly by ellipsometry, and that the refractive index measured by such a method and the substrate temperature have an excellent linear relationship in a practical region. Is. And according to the method of the present invention, the temperature of the substrate can be accurately measured.
（ニ）問題点を解決するための手段およひ作用 かくしてこの発明にれば、基板を所定温度に加熱してそ
の上に薄膜を成長さす際に、基板の屈折率をエリプソメ
トリーにより測定し、この屈折率の温度依存性に基づい
て該基板の温度を検知することを特徴とする基板温度の
測定法が提供される。(D) Means and Actions for Solving the Problems Thus, according to the present invention, when the substrate is heated to a predetermined temperature and a thin film is grown thereon, the refractive index of the substrate is measured by ellipsometry. A method for measuring a substrate temperature is provided, which comprises detecting the temperature of the substrate based on the temperature dependence of the refractive index.
この発明に用いられる基板としては、前述のごときＥＢ
法、ＩＣＢ法、ＭＢＥ法、ＣＶＤ法、ＭＯＣＶＤ法等に
おいて適用される種々の基板を使用することができる。
この発明の測温法は上記基板上に薄膜を成長さす際に基
板初期温度の測定制御に好適に用いられる。The substrate used in this invention is EB as described above.
Various substrates applied in the method, ICB method, MBE method, CVD method, MOCVD method, etc. can be used.
The temperature measuring method of the present invention is suitably used for measuring and controlling the initial temperature of a substrate when growing a thin film on the substrate.
この発明に適用し屈折率を測定するために用いるエリプ
ソメトリーは通常、偏光反射法、楕円偏光解析法とも呼
ばれており、被測定物体表面において所定角度で反射す
る偏光の偏光面や強度の変化に基づいて、被測定物体の
表面の物理定数を決定する方法である。かかる方法は、
被測定物体の屈折率や厚みの測定に使用することは知ら
れているが、温度の測定に応用することは知られていな
い。Ellipsometry applied to the present invention and used to measure the refractive index is usually called polarization reflection method or ellipsometry, and changes in the polarization plane or intensity of polarized light reflected at a predetermined angle on the surface of the object to be measured. Is a method of determining the physical constants of the surface of the object to be measured based on. Such a method
It is known to be used for measuring the refractive index and thickness of an object to be measured, but is not known to be used for measuring temperature.
エリプソメトリーを行なうために使用するエリプソメー
タは通常用いられるものが適用できる。このエリプソメ
ータは光源，光源から照射された光を直線偏光とし方位
角を調整することのできる偏光子，方位角を固定する波
長板および試料によって反射された直線偏光の傾きを検
出する検出子を基本的に備えて構成される。またエリプ
ソメータをこの発明の方法に適用するために薄膜成長室
は、通常入射光および反射光のための光学窓を両側面に
備えたものが用いられる。As the ellipsometer used for performing the ellipsometry, a commonly used ellipsometer can be applied. This ellipsometer is based on a light source, a polarizer that can adjust the azimuth angle of light emitted from the light source as linearly polarized light, a wave plate that fixes the azimuth angle, and a detector that detects the inclination of the linearly polarized light reflected by the sample. Be prepared for the purpose. Further, in order to apply the ellipsometer to the method of the present invention, the thin film growth chamber is usually provided with optical windows on both sides for incident light and reflected light.
この測温法のためにまずエリプソメトリーを用いて所定
温度ごとに基板の屈折率を測定し、基板温度に対する屈
折率の温度較正グラフを作成する。以後は屈折率を測定
し当該温度較正グラフを用いてその屈折率に該当する温
度をグラフ上より得ることによって測温がおこなわれ
る。For this temperature measurement method, first, the refractive index of the substrate is measured for each predetermined temperature using ellipsometry, and a temperature calibration graph of the refractive index with respect to the substrate temperature is created. After that, the temperature is measured by measuring the refractive index and using the temperature calibration graph to obtain the temperature corresponding to the refractive index from the graph.
この測温法は薄膜の成長前特に基板の表面清浄化がなさ
れた状態において行ない、基板温度を最適化させてから
基板を薄膜成長に付すのが適切である。しかしながら成
長物質が基板と同材質の場合薄膜の成長中においても、
薄膜成長のための薄膜表面の不安定性のために多少誤差
はでるが、有効である。勿論途中で成長を止めて測温す
ることもできる。It is appropriate that this temperature measuring method is performed before the growth of the thin film, especially in the state where the surface of the substrate is cleaned, and the substrate temperature is optimized before the substrate is subjected to the thin film growth. However, when the growth material is the same material as the substrate, even during the growth of the thin film,
It is effective although there is some error due to instability of the thin film surface for thin film growth. Of course, it is also possible to stop the growth on the way and measure the temperature.
基板物質と薄膜とが異物質の場合は、基板表面と薄膜と
の界面で偏光が変化するため、この変化を補償する必要
があり好ましくない。When the substrate substance and the thin film are different substances, the polarization changes at the interface between the substrate surface and the thin film, and this change needs to be compensated, which is not preferable.
（ホ）実施例 以下この発明をＭＢＥ成長において基板としてＧａＡｓ
を用い、屈折率測定をエリプソメータを用いて行なった
実施例により説明する。なおこの実施例により本発明は
限定されるものではない。(E) Example In the present invention, GaAs is used as a substrate for MBE growth.
And an example in which the refractive index is measured using an ellipsometer. The present invention is not limited to this embodiment.
第１図はエリプソメータが設置された成長室の概略図で
ある。入射光はＨｅ−Ｎｅレーザ（6328Å）(1)から偏
光子(2)、１／４波長板(3)及び光学窓（20mmφ）(4)を
通り成長室に入りサセプター(5)にマウントされたＧａ
Ａｓ基板(6)で反射された光学窓（20mmφ）(7)を通り成
長室外に出て検光子(8)からフォトマルチプライヤ(9)に
入る。偏光子、１／４波長板、検光子の回転及びフォト
マルチプライヤの出力処理はすべてコントローラ(10)に
より制御され自動的に消光点を求めてそれにより屈折率
が決定できるようにした。また入射角(11)はエリプソメ
トリーの感度を上げるためＧａＡｓのブリュースター角
（約76°）に近い74°に設定した。FIG. 1 is a schematic view of a growth chamber in which an ellipsometer is installed. Incident light passes from a He-Ne laser (6328Å) (1) through a polarizer (2), a quarter wave plate (3) and an optical window (20mmφ) (4) into a growth chamber and is mounted on a susceptor (5). Ga
It goes out of the growth chamber through the optical window (20 mmφ) (7) reflected by the As substrate (6) and enters the photomultiplier (9) from the analyzer (8). The polarizer, the quarter-wave plate, the rotation of the analyzer, and the output processing of the photomultiplier are all controlled by the controller (10) so that the extinction point is automatically obtained and the refractive index can be determined accordingly. The incident angle (11) was set at 74 °, which is close to the Brewster angle (about 76 °) of GaAs in order to increase the sensitivity of ellipsometry.
第２図にエリプソメータの備わった恒温槽にＧａＡｓ基
板を入れＧａＡｓＭＢＥ成長で用いられる基板温度領域
（550℃〜650℃）でのＧａＡｓの屈折率の温度依存性を
調べた結果を示す。さて実際に赤外線反射温度計測定が
有効なソルダ・マウント方式のサセプターにＧａＡｓ基
板をＩｎでマウントし第１図の成長室に搬送しＡｓ補給
用のＡｓ分子線おみを基板に照射した状態で赤外線放射
温度計指示で基板温度を500℃から700℃まで２℃ステッ
プで変化させ各基板温度毎に第１図のエリプソメータよ
り基板の屈折率を求め第２図の較正グラフより基板温度
を求めた。既述のように信頼するに足るソルダ・マウン
ト方式の赤外線放射温度計の指示値と本測温法のそれを
比較したところ±０．５℃の誤差で両者の一致が見ら
れ、この発明の測温法の精度は非常に精度が高いことが
判明した。FIG. 2 shows the results of investigating the temperature dependence of the refractive index of GaAs in the substrate temperature range (550 ° C. to 650 ° C.) used for GaAs MBE growth by placing the GaAs substrate in a thermostat equipped with an ellipsometer. Now, in a state where the GaAs substrate was mounted with In on the susceptor of the solder mount system in which the infrared reflection thermometer measurement is actually effective, the substrate was transferred to the growth chamber of FIG. 1 and the substrate was irradiated with As molecular beam dust for As replenishment. The infrared radiation thermometer was used to change the substrate temperature from 500 ° C to 700 ° C in 2 ° C steps, and the refractive index of the substrate was obtained from the ellipsometer in Fig. 1 for each substrate temperature, and the substrate temperature was obtained from the calibration graph in Fig. 2. . As described above, when comparing the indicated value of the infrared radiation thermometer of the solder mount type which is reliable enough and that of this temperature measuring method, the agreement of both is found with an error of ± 0.5 ° C. It turned out that the accuracy of the temperature measuring method is very high.
（ヘ）発明の効果 この発明の基板温度の測定法は基板物質の物性を直接利
用しているため基板とサセプターの密着状況やサセプタ
ーの種類などに全く依存せず基板温度の測定ができる。
従って、通常の薄膜形成法において薄膜成長の重要なパ
ラメータである基板温度を厳密に設定することができて
再現性のよい薄膜を得ることができる。従って前述のご
とき種々の薄膜の形成前の基板の温度制御用として有用
でありことに厳密な温度制御を必要とされるＭＢＥ法に
有用である。(F) Effect of the Invention Since the substrate temperature measuring method of the present invention directly utilizes the physical properties of the substrate material, the substrate temperature can be measured without depending on the adhesion state of the substrate and the susceptor or the kind of the susceptor.
Therefore, the substrate temperature, which is an important parameter for thin film growth in the ordinary thin film forming method, can be set precisely, and a thin film with good reproducibility can be obtained. Therefore, it is useful for controlling the temperature of the substrate before forming various thin films as described above, and is particularly useful for the MBE method which requires strict temperature control.
第１図はこの発明の測定法を実施する装置及び実施状態
を示す概略図、第２図はエリプソメータで測定したＧａ
Ａｓ基板の屈折率より基板温度換算するために用いる較
正直線を示すグラフである。 (1)……Ｈｅ−Ｎｅレーザ、(2)……偏光子、 (3)……１／４波長板、 (4)……光学窓、 (5)……サセプター、 (6)……ＧａＡｓ基板、 (7)……光学窓、 (8)……検光子、 (9)……フォトマルチプライヤ、 (10)……コントローラ、 (11)……入射角。FIG. 1 is a schematic diagram showing an apparatus for carrying out the measurement method of the present invention and an implementation state, and FIG. 2 is a Ga measured by an ellipsometer.
It is a graph which shows the calibration straight line used in order to carry out substrate temperature conversion from the refractive index of As substrate. (1) ... He-Ne laser, (2) ... polarizer, (3) ... quarter wave plate, (4) ... optical window, (5) ... susceptor, (6) ... GaAs Substrate, (7) …… optical window, (8) …… analyzer, (9) …… photomultiplier, (10) …… controller, (11) …… incident angle.
Claims (1)
成長さす際に、 基板の屈折率をエリプソメトリーにより測定し、この屈
折率の温度依存性に基づいて該基板の温度を検知するこ
とを特徴とする基暗温度の測定法。1. When a substrate is heated to a predetermined temperature to grow a thin film thereon, the refractive index of the substrate is measured by ellipsometry, and the temperature of the substrate is detected based on the temperature dependence of this refractive index. A method for measuring a base dark temperature, which is characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19904885A JPH067072B2 (en) | 1985-09-09 | 1985-09-09 | Substrate temperature measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19904885A JPH067072B2 (en) | 1985-09-09 | 1985-09-09 | Substrate temperature measurement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6258141A JPS6258141A (en) | 1987-03-13 |
| JPH067072B2 true JPH067072B2 (en) | 1994-01-26 |
Family
ID=16401244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19904885A Expired - Fee Related JPH067072B2 (en) | 1985-09-09 | 1985-09-09 | Substrate temperature measurement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH067072B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102507040A (en) * | 2011-11-10 | 2012-06-20 | 复旦大学 | Thin film temperature measurement method based on ellipsometer |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2007066687A1 (en) * | 2005-12-06 | 2009-05-21 | 株式会社ニコン | Temperature measurement method, exposure method, exposure apparatus, and device manufacturing method |
-
1985
- 1985-09-09 JP JP19904885A patent/JPH067072B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102507040A (en) * | 2011-11-10 | 2012-06-20 | 复旦大学 | Thin film temperature measurement method based on ellipsometer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6258141A (en) | 1987-03-13 |
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