JP2740903B2 - Evaluation method for compound semiconductor substrate - Google Patents
Evaluation method for compound semiconductor substrateInfo
- Publication number
- JP2740903B2 JP2740903B2 JP4298577A JP29857792A JP2740903B2 JP 2740903 B2 JP2740903 B2 JP 2740903B2 JP 4298577 A JP4298577 A JP 4298577A JP 29857792 A JP29857792 A JP 29857792A JP 2740903 B2 JP2740903 B2 JP 2740903B2
- Authority
- JP
- Japan
- Prior art keywords
- compound semiconductor
- semiconductor substrate
- photoluminescence
- emission intensity
- intensity
- 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
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- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、化合物半導体基板の評
価技術さらにはフォトルミネッセンス効果を利用した化
合物半導体基板の評価方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for evaluating a compound semiconductor substrate and, more particularly, to a method for evaluating a compound semiconductor substrate utilizing a photoluminescence effect.
【０００２】[0002]
【従来の技術】化合物半導体基板を用いた半導体デバイ
スの特性は、使用する化合物半導体基板の品質に依存す
る。従来、化合物半導体基板の評価方法として、例えば
レーザ光を励起光として用いたフォトルミネッセンス法
が広く利用されている。従来のフォトルミネッセンス法
による化合物半導体基板の評価は、絶対温度４Ｋあるい
は７７Ｋといった低温で高出力のレーザを用いて基板を
励起し、結晶内部の欠陥（非発光中心）の同定を、発光
スペクトルの波長、強度を分析することで行なってい
た。2. Description of the Related Art The characteristics of a semiconductor device using a compound semiconductor substrate depend on the quality of the compound semiconductor substrate used. Conventionally, as a method for evaluating a compound semiconductor substrate, for example, a photoluminescence method using laser light as excitation light has been widely used. The evaluation of a compound semiconductor substrate by the conventional photoluminescence method involves exciting the substrate using a high-power laser at a low temperature of 4 K or 77 K, identifying defects (non-emission centers) inside the crystal, and determining the wavelength of the emission spectrum. And by analyzing the strength.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記従
来の低温フォトルミネッセンス法は、液体窒素や液体ヘ
リウムを入れたデュワー瓶のような大がかりな装置が必
要であり、また冷却にも数時間〜半日といった長い時間
を要するという問題点があった。However, the above-mentioned conventional low-temperature photoluminescence method requires a large-scale apparatus such as a dewar containing liquid nitrogen or liquid helium, and requires several hours to half a day for cooling. There is a problem that it takes a long time.
【０００４】また、従来、フォトルミネッセンス法は、
半導体基板上に成長させたエピタキシャル膜の評価にも
利用されていたが、その場合には、上記低温による結晶
欠陥評価の他に、エピタキシャル膜（特に混晶膜）の組
成を知るために室温でその発光波長を測定することが行
なわれていた。ところが、エピタキシャル膜成長プロセ
ス（ＭＯＣＶＤ法）の再現性等が良好でなかったため、
エピタキシャル膜について測定されたフォトルミネッセ
ンスの発光強度の違いは、主としてプロセスばらつきに
起因するエピタキシャル膜の品質の違いによって生じる
と考えられていた。[0004] Conventionally, the photoluminescence method,
It has also been used for evaluation of epitaxial films grown on semiconductor substrates. In this case, in addition to the above-described evaluation of crystal defects at low temperatures, in order to know the composition of epitaxial films (especially mixed crystal films), the temperature was measured at room temperature. The emission wavelength was measured. However, since the reproducibility of the epitaxial film growth process (MOCVD method) was not good,
It was thought that the difference in the photoluminescence emission intensity measured for the epitaxial film was mainly caused by the difference in the quality of the epitaxial film due to process variation.
【０００５】本発明は上記のような背景の下になされた
もので、その目的とするところは、化合物半導体基板の
品質を簡単な装置でしかも室温において簡便に評価でき
るような基板評価方法を提供することにある。The present invention has been made in view of the above background, and an object of the present invention is to provide a method for evaluating the quality of a compound semiconductor substrate which can be easily evaluated at a room temperature with a simple apparatus. Is to do.
【０００６】[0006]
【課題を解決するための手段】本発明者等は、多数の半
導体基板上に同時にエピタキシャル膜を成長できる装置
を用いてエピタキシャル成長を行ない、得られたエピタ
キシャル膜の品質を室温でのフォトルミネッセンス法を
適用して評価してみた。このように同一の装置で同時に
成長されたエピタキシャル膜は同一の品質を有するはず
である。ところが、結果は、同じロットの半導体基板上
に成長されたエピタキシャル膜の発光強度はほぼ同一で
あるが、異なるロットの半導体基板上に成長されたエピ
タキシャル膜の発光強度は異なっていることが分かっ
た。Means for Solving the Problems The present inventors performed epitaxial growth using an apparatus capable of simultaneously growing an epitaxial film on a large number of semiconductor substrates, and evaluated the quality of the obtained epitaxial film by a photoluminescence method at room temperature. I applied and evaluated. Thus, epitaxial films grown simultaneously in the same apparatus should have the same quality. However, the results show that the luminescence intensities of the epitaxial films grown on the semiconductor substrates of the same lot are almost the same, but the luminescence intensities of the epitaxial films grown on the semiconductor substrates of different lots are different. .
【０００７】これより、本発明者らは、フォトルミネッ
センスの発光強度はエピタキシャル膜そのものの品質で
はなく基板の品質を反映しているとの結論に達した。そ
こで、次に、基板表面に照射するレーザ光の強さすなわ
ちフォトルミネッセンス励起強度を変えて、異なるロッ
トの半導体基板上に成長されたエピタキシャル膜の発光
強度を測定した。その結果、図１に示すように、フォト
ルミネッセンス励起強度が低くなるとロットによって発
光強度に違いが現われることを見出した。Thus, the present inventors have concluded that the photoluminescence emission intensity reflects not the quality of the epitaxial film itself but the quality of the substrate. Then, next, the intensity of the laser beam irradiated on the substrate surface, that is, the photoluminescence excitation intensity was changed, and the emission intensity of the epitaxial films grown on the semiconductor substrates of different lots was measured. As a result, as shown in FIG. 1, it was found that when the photoluminescence excitation intensity was low, the emission intensity was different depending on the lot.
【０００８】この発明は、上記のような知見に基いてな
されたもので、化合物半導体基板上に、当該半導体基板
の組成と異なる組成の化合物半導体層をエピタキシャル
成長させ、この化合物半導体層の上方より４０ｍＷ以下
の低出力レーザ光を照射して弱励起し、励起キャリア数
に対する再結合キャリア数の比率を大きくした後、フォ
トルミネッセンスによる発光強度を測定することによ
り、当該化合物半導体基板の品質を評価することを提案
するものである。なお、半導体基板上に成長される半導
体層の組成は半導体基板と異なる組成であるとしたの
は、原理的には同一組織であっても、エピタキシャル層
の発光強度には差を生じ、測定は可能であるが、両者の
組成が同一であると励起時にエピタキシャル層と半導体
基板の双方が励起されてしまって、差が分からなくなっ
てしまうためである。The present invention has been made on the basis of the above-described findings. A compound semiconductor layer having a composition different from the composition of the semiconductor substrate is epitaxially grown on the compound semiconductor substrate, and 40 mW from above the compound semiconductor layer. Evaluating the quality of the compound semiconductor substrate by irradiating the following low-power laser light to weakly excite, increasing the ratio of the number of recombined carriers to the number of excited carriers, and then measuring the emission intensity by photoluminescence. Is proposed. Note that the composition of the semiconductor layer grown on the semiconductor substrate is different from the composition of the semiconductor substrate. Even in principle, even if the composition is the same, a difference occurs in the emission intensity of the epitaxial layer. Although it is possible, if the compositions of the two are the same, both the epitaxial layer and the semiconductor substrate are excited at the time of excitation, and the difference cannot be recognized.
【０００９】[0009]
【作用】フォトルミネッセンスによる発光強度Ｉは、Ｉ
＝（励起されたキャリアの数−非発光中心で再結合した
キャリアの数）で表わされる。ここで、非発光中心は結
晶中の欠陥や表面に存在すると考えられるので、上記励
起キャリア数が励起強度に比例するのに対し、上記再結
合キャリア数はエピタキシャル膜に固有の一定数にな
る。そのため、基板を励起させるレーザ光の強度が高い
と励起キャリア数に対する再結合キャリア数の比率が小
さいので結晶中の欠陥密度や表面状態の良否の発光強度
に対する影響が小さいが、励起させるレーザ光の強度が
低いと励起キャリア数に対する再結合キャリア数の比率
が大きいので結晶中の欠陥密度や表面状態の良否の発光
強度に対する影響が大きくなる。The light emission intensity I due to photoluminescence is I
= (Number of excited carriers-number of carriers recombined at the non-emission center). Here, since the non-emission center is considered to be present in a defect or surface in the crystal, the number of the excited carriers is proportional to the excitation intensity, whereas the number of the recombination carriers is a constant constant peculiar to the epitaxial film. Therefore, when the intensity of the laser beam for exciting the substrate is high, the ratio of the number of recombination carriers to the number of excited carriers is small, so that the defect density in the crystal and the quality of the surface state have little effect on the emission intensity. When the intensity is low, the ratio of the number of recombined carriers to the number of excited carriers is large, so that the influence of the defect density in the crystal and the quality of the surface state on the emission intensity increases.
【００１０】しかるに、上記した手段によれば、４０ｍ
Ｗ以下の低出力のレーザ光を照射して弱励起させている
ため、結晶中の欠陥密度や表面状態の良否の発光強度に
対する影響が相対的に大きくなり、フォトルミネッセン
スによる発光強度を測定することにより、その強度が高
いときは結晶中の欠陥密度が低く表面状態が良好である
と、また測定された発光強度が低いときは結晶中の欠陥
密度が高く表面状態が良好でないと判定することができ
る。また、上記フォトルミネッセンスによる発光強度の
測定は室温にて行うことができる。[0010] However, according to the above means, 40 m
Since the laser beam is weakly excited by irradiating a low-power laser beam of W or less, the influence of the defect density in the crystal and the quality of the surface state on the light emission intensity becomes relatively large, and the light emission intensity by photoluminescence must be measured. Thus, when the intensity is high, the defect density in the crystal is low and the surface state is good, and when the measured emission intensity is low, it is determined that the defect density in the crystal is high and the surface state is not good. it can. The measurement of the light emission intensity by the photoluminescence can be performed at room temperature.
【００１１】[0011]
【実施例】ロットの異なる複数枚のＺｎドープＩｎＰ基
板（キャリア濃度３×１０18cm-3）を用意し、成長装置
のサセプタ上にこれらの基板を配置した。そしてＭＯＣ
ＶＤ（有機金属気相成長）法により、上記複数の基板上
に同時に厚み０．１μｍのＧａ0.28Ｉｎ0.72Ａｓ0.39Ｐ
0.61層をエピタキシャル成長させた。この基板の上方よ
り、室温にて波長５１４５．３ÅのＡｒ+レーザ光（ス
ポット径８００μｍ）を照射して、基板の中心部でのフ
ォトルミネッセンスによる発光強度を測定した。レーザ
光による励起強度は、５ｍＷから１００ｍＷまで変化さ
せた。測定波長は１．３μｍで、検出器にはＧｅ製のフ
ォトダイオードを用いた。EXAMPLE A plurality of Zn-doped InP substrates (carrier concentration: 3 × 10 18 cm −3 ) of different lots were prepared, and these substrates were arranged on a susceptor of a growth apparatus. And MOC
The VD (metal organic chemical vapor deposition) method, Ga 0. 28 In 0 simultaneously thickness 0.1μm on the plurality of substrates. 72 As 0. 39 P
The 0.61 layer was grown epitaxially. An Ar + laser beam (spot diameter 800 μm) having a wavelength of 5145.3 ° was irradiated from above the substrate at room temperature, and the light emission intensity due to photoluminescence at the center of the substrate was measured. The excitation intensity by the laser light was changed from 5 mW to 100 mW. The measurement wavelength was 1.3 μm, and a photodiode made of Ge was used for the detector.
【００１２】図１に測定結果を示す。同図において、○
印は一方のロット１のＩｎＰ基板について測定した発光
強度を、また●印は他方のロット２のＩｎＰ基板につい
て測定した発光強度を示す。同図より、５０ｍＷ以上の
強励起では２つのロット１，２の発光強度間に差は見ら
れないが、４０ｍＷ以下の弱励起では２つのロット１，
２の発光強度間に差が見られるようになることが分か
る。FIG. 1 shows the measurement results. In FIG.
The mark indicates the emission intensity measured for the InP substrate of one lot 1, and the mark ● indicates the emission intensity measured for the InP substrate of the other lot 2. From the figure, there is no difference between the emission intensities of the two lots 1 and 2 with the strong excitation of 50 mW or more, but the two lots 1 and 2 with the weak excitation of 40 mW or less.
It can be seen that there is a difference between the two emission intensities.
【００１３】上記の場合、励起させるレーザ光の強度が
低いと励起キャリア数に対する再結合キャリア数の比率
が大きいので結晶中の欠陥密度や表面状態の良否の発光
強度に対する影響が大きくなる。そのため、測定された
発光強度が高いときは結晶中の欠陥密度が低く表面状態
が良好で基板は高品質であると、また測定された発光強
度が低いときは結晶中の欠陥密度が高く表面状態は良好
でなく基板は低品質であると判定することができる。な
お、上記実施例では、基板励起用のレーザ光としてＡｒ
+レーザ光を用いたが、本発明の原理からすればＨｅ−
Ｎｅ，Ｈｅ−Ｃｄ，ＹＡＧその他のレーザ光を用いても
よいことはいうまでもない。また、温度も室温に限定さ
れず、低温で励起を行なうようにしてもよい。In the above case, when the intensity of the laser light to be excited is low, the ratio of the number of recombination carriers to the number of excited carriers is large, so that the defect density in the crystal and the quality of the surface state have a great influence on the emission intensity. Therefore, when the measured luminescence intensity is high, the defect density in the crystal is low and the surface condition is good, and the substrate is of high quality. When the measured luminescence intensity is low, the defect density in the crystal is high and the surface condition is high. Is not good and the substrate is of low quality. In the above embodiment, the laser light for exciting the substrate is Ar
+ Laser light was used, but according to the principle of the present invention, He-
Needless to say, Ne, He-Cd, YAG or other laser light may be used. Further, the temperature is not limited to room temperature, and the excitation may be performed at a low temperature.
【００１４】[0014]
【発明の効果】以上説明したように、この発明は、化合
物半導体基板上に、当該半導体基板の組成と異なる組成
の化合物半導体層をエピタキシャル成長させ、この化合
物半導体層の上方より４０ｍＷ以下の低出力レーザ光を
照射して弱励起し、化合物半導体層における励起キャリ
ア数に対する再結合キャリア数の比率を大きくした後、
フォトルミネッセンスによる発光強度を測定することに
より、当該化合物半導体基板の品質を評価するようにし
たので、結晶中の欠陥密度や表面状態の良否の発光強度
に対する影響が相対的に大きくなり、フォトルミネッセ
ンスによる発光強度を測定することにより、その強度が
高いときは結晶中の欠陥密度が低く表面状態が良好であ
ると、また、測定された発光強度が低いときは結晶中の
欠陥密度が高いか、表面状態が良好でないと判定するこ
とができるため、簡単な装置で化合物半導体基板の品質
を評価することができるという効果がある。しかも、上
記フォトルミネッセンスによる発光強度の測定は室温に
て行なうことができる。As described above, according to the present invention, a compound semiconductor layer having a composition different from that of the semiconductor substrate is epitaxially grown on the compound semiconductor substrate, and a low-power laser of 40 mW or less is provided from above the compound semiconductor layer. After irradiating light to weakly excite and increase the ratio of the number of recombination carriers to the number of excited carriers in the compound semiconductor layer,
Since the quality of the compound semiconductor substrate is evaluated by measuring the light emission intensity by photoluminescence, the influence on the light emission intensity of the defect density in crystal and the quality of the surface state becomes relatively large, and the light emission intensity by photoluminescence is increased. By measuring the emission intensity, when the intensity is high, the defect density in the crystal is low and the surface condition is good, and when the measured emission intensity is low, the defect density in the crystal is high or Since it can be determined that the state is not good, there is an effect that the quality of the compound semiconductor substrate can be evaluated with a simple device. Moreover, the measurement of the emission intensity by the photoluminescence can be performed at room temperature.
【図１】フォトルミネッセンス励起強度と発光強度との
関係をロット別に示すグラフである。FIG. 1 is a graph showing the relationship between photoluminescence excitation intensity and emission intensity for each lot.
Claims (1)
組成と異なる組成の化合物半導体層をエピタキシャル成
長させ、 この化合物半導体層の上方より４０ｍＷ以下の低出力レ
ーザ光を照射して弱励起し、化合物半導体層における励
起キャリア数に対する再結合キャリア数の比率を大きく
した後、 フォトルミネッセンスによる発光強度を測定することに
より、当該化合物半導体基板の品質を評価するようにし
たことを特徴とする化合物半導体基板の評価方法。A compound semiconductor layer having a composition different from that of the semiconductor substrate is epitaxially grown on the compound semiconductor substrate, and a low-power laser beam of 40 mW or less is irradiated from above the compound semiconductor layer to weakly excite the compound semiconductor layer. After increasing the ratio of the number of recombination carriers to the number of excited carriers in the semiconductor layer, by measuring the emission intensity by photoluminescence, the quality of the compound semiconductor substrate is evaluated. Evaluation method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4298577A JP2740903B2 (en) | 1992-11-09 | 1992-11-09 | Evaluation method for compound semiconductor substrate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4298577A JP2740903B2 (en) | 1992-11-09 | 1992-11-09 | Evaluation method for compound semiconductor substrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06151540A JPH06151540A (en) | 1994-05-31 |
| JP2740903B2 true JP2740903B2 (en) | 1998-04-15 |
Family
ID=17861548
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4298577A Expired - Lifetime JP2740903B2 (en) | 1992-11-09 | 1992-11-09 | Evaluation method for compound semiconductor substrate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2740903B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110544643A (en) * | 2019-09-11 | 2019-12-06 | 东方日升（常州）新能源有限公司 | Method for rapidly judging burning-through depth of metal slurry without damage |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4287692B2 (en) * | 2003-04-25 | 2009-07-01 | 凸版印刷株式会社 | Stress evaluation method for compound thin film of amorphous silicon |
| JP5192661B2 (en) * | 2006-05-29 | 2013-05-08 | 一般財団法人電力中央研究所 | Method for manufacturing silicon carbide semiconductor element |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2661977B2 (en) * | 1988-08-18 | 1997-10-08 | 日本電信電話株式会社 | Identification of trace impurities in semiconductor crystals. |
-
1992
- 1992-11-09 JP JP4298577A patent/JP2740903B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110544643A (en) * | 2019-09-11 | 2019-12-06 | 东方日升（常州）新能源有限公司 | Method for rapidly judging burning-through depth of metal slurry without damage |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06151540A (en) | 1994-05-31 |
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