JP2703324B2 - Optical absorption coefficient measuring device - Google Patents
Optical absorption coefficient measuring deviceInfo
- Publication number
- JP2703324B2 JP2703324B2 JP8310389A JP8310389A JP2703324B2 JP 2703324 B2 JP2703324 B2 JP 2703324B2 JP 8310389 A JP8310389 A JP 8310389A JP 8310389 A JP8310389 A JP 8310389A JP 2703324 B2 JP2703324 B2 JP 2703324B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- absorption coefficient
- reflectance
- light absorption
- transmittance
- 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
Landscapes
- Investigating Or Analysing Materials By Optical Means (AREA)
Description
【発明の詳細な説明】 （イ）産業上の利用分野 本発明は半導体、絶縁体、或は金属等の薄膜の光吸収
係数測定装置に関する。The present invention relates to an apparatus for measuring a light absorption coefficient of a thin film such as a semiconductor, an insulator or a metal.
（ロ）従来の技術 薄膜の光吸収係数を測定する方法としては従来光透過
率Ｔと光反射率Ｒを測定し、両率Ｔ、Ｒの二つの光吸収
係数αｋに関する理論的な連立方程式を解くことによっ
て、目的の光吸収係数αｋを求めていた（S.G.Tomlin e
t al.J.PHYS.D2−１（1968）P1667〜1671参照）。(B) Conventional technology As a method for measuring the light absorption coefficient of a thin film, a conventional system of measuring a light transmittance T and a light reflectance R, and calculating a theoretical simultaneous equation concerning two light absorption coefficients α k of the two factors T and R is known. To obtain the desired light absorption coefficient α k (SGTomlin e
tal. J. PHYS. D2-1 (1968) P1667 to 1671).
しかしながら上記方法では、光干渉が顕著な波長領域
において第１図に示すように光透過率Ｔや光反射率Ｒの
ふれが大きくなり、光吸収係数αｋの測定精度が悪くな
っていた。従って光吸収係数αｋを精度良く測定できる
のは、光干渉が顕著でない波長領域に限られてしまって
いた。However, in the above method, as shown in FIG. 1, the fluctuation of the light transmittance T and the light reflectance R becomes large in the wavelength region where the light interference is remarkable, and the measurement accuracy of the light absorption coefficient α k is deteriorated. Therefore, accurate measurement of the light absorption coefficient α k is limited to a wavelength region where light interference is not remarkable.
（ハ）発明が解決しようとする課題 本発明が解決しようとする課題は光干渉が顕著に見ら
れる波長領域において、光吸収係数αｋを光干渉が顕著
でない領域と同様に精度良く測定できる演算上の手法を
開発することである。(C) Problems to be Solved by the Invention The problem to be solved by the present invention is to calculate the light absorption coefficient α k in the wavelength region where light interference is remarkable as well as in the region where light interference is not remarkable. It is to develop the above method.
（ニ）課題を解決するための手段 薄膜の光透過率Ｔと光反射率Ｒとを検出する検出器
と、該検出器の光透過率Ｔ及び光反射率Ｒのデータに基
づいてT/（１−Ｒ）の演算を行いその演算結果を用いて
前記薄膜の光吸収係数を算出するマイクロプロセッサと
より成る。(D) Means for Solving the Problems A detector for detecting the light transmittance T and the light reflectance R of the thin film, and T / (based on the data of the light transmittance T and the light reflectance R of the detector. 1-R) and a microprocessor for calculating the light absorption coefficient of the thin film using the calculation result.
（ホ）作用 光透過率Ｔと光反射率Ｒはその光干渉領域において相
補関係に近い状態にあり、即ち光透過率Ｔの高い波長で
は光反射率Ｒが低く、逆に光透過率Ｔの低いところでは
光反射率Ｒが高くなる。このためT/（１−Ｒ）の演算を
行ってやれば、双方が打ち消しあって光干渉による測定
値の変動が緩和される。(E) Action The light transmittance T and the light reflectance R are close to a complementary relationship in the light interference region, that is, the light reflectance R is low at a wavelength where the light transmittance T is high, and conversely, the light transmittance T is low. In a low place, the light reflectance R increases. Therefore, if the calculation of T / (1−R) is performed, the two cancel each other out, and the fluctuation of the measured value due to the optical interference is reduced.
（ヘ）実施例 以下本発明を図面の一実施例について詳細に説明す
る。(F) Example Hereinafter, the present invention will be described in detail with reference to an example of the drawings.
第１図に本発明光吸収係数の測定装置の一実施例を示
す。同図において、（Ｌ）はハロゲンランプ光源、（M
1）〜（M3）はミラー、（Ｓ）は薄膜の試料、（LS）は
参照光、（LD）は検出光、（Ｄ）は両参照光（LS）と検
出光（LD）とを入力し、反射率Ｒ（第１図上側）、若し
くは透過率Ｔ（同図下側）を検出する検出器、（MC）は
前記検出器（Ｄ）空の出力データＲ又はＴより光吸収係
数αｋを算出するマイクロプロセッサである。FIG. 1 shows an embodiment of the optical absorption coefficient measuring apparatus of the present invention. In the figure, (L) is a halogen lamp light source, (M)
1) ~ (M3) is a mirror, (S) sample of film, (L S) is the reference light, (L D) is detected light, (D) Both the reference light (L S) and the detection light (L D ), And detects the reflectance R (upper side in FIG. 1) or the transmittance T (lower side in FIG. 1). (MC) is based on the detector (D) empty output data R or T. It is a microprocessor that calculates the light absorption coefficient α k .
尚第１図上側と下側の光源（Ｌ）から検出器（Ｄ）ま
でのシステムは共通であり、試料（Ｓ）はしたがって全
く同じものである。実際には、最初に検出器（Ｄ）を介
して反射率Ｒを測定し、その後ミラー（M1）〜（M3）の
配置を換えて透過率Ｔを測定し、両方のデータが出揃っ
た上で光吸収係数αｋを検出することになる。The system from the light source (L) to the detector (D) on the upper and lower sides in FIG. 1 is common, and the sample (S) is therefore exactly the same. Actually, first, the reflectance R is measured via the detector (D), and then the transmittance T is measured by changing the arrangement of the mirrors (M1) to (M3). The light absorption coefficient α k will be detected.
次に第２図は薄膜約１μｍのａ−Si:Hの透過率Ｔ、反
射率Ｒ、及び透過率T/（１−反射率Ｒ）の波長に対する
データを示す。同図から明らかなように反射率Ｒ、透過
率Ｔは共に波長600nmから800nmの範囲で干渉が顕著であ
る。Next, FIG. 2 shows the data for the transmittance T, the reflectance R, and the wavelength of the transmittance T / (1−reflectance R) of a-Si: H of about 1 μm of the thin film. As can be seen from the figure, both the reflectance R and the transmittance T show significant interference in the wavelength range of 600 nm to 800 nm.
ところで上記T/（１−Ｒ）と光吸収係数αｋ都の間に
は以下の関係がある。Incidentally, the following relationship exists between T / (1-R) and the light absorption coefficient α k .
nk:媒質ｋの屈折率、αk:媒質ｋの光吸収係数（媒質
０、１、２、３はそれぞれ空気、ａ−Si:H、ガラス、空
気である） λ：光の波長、d:a−SiHの膜厚 さて前記（１）式の値は光透過率Ｔ及び光反射率Ｒの
測定データより算出でき、且つ第２図から明らかなよう
にT/（１−Ｒ）は、波長400nm〜800nmにわたって光干渉
が除去されているから（１）式をαｋについて解けば、
光吸収係数αｋが求められる。こうして得られた光吸収
係数αｋの波長に対するデータを第３図に示す（但し、
この実施例では透過率Ｔ、反射率Ｒの測定機の精度が、
±３％程度であるので、３％＜T/（１−Ｒ）＜97％の範
囲、即ち約550nm〜770nmの範囲で光吸収係数を測定し
た。後述する実施例においても光吸収係数の測定精度は
測定方法ではなく使用される測定機の精度で律速されて
いる）。 n k : refractive index of medium k, α k : light absorption coefficient of medium k (mediums 0, 1, 2, and 3 are air, a-Si: H, glass, and air, respectively) λ: wavelength of light, d : a-SiH film thickness The value of the above equation (1) can be calculated from the measured data of the light transmittance T and the light reflectance R, and as is clear from FIG. Since optical interference is eliminated over a wavelength of 400 nm to 800 nm, solving equation (1) for α k gives
The light absorption coefficient α k is obtained. The data for the wavelength of the light absorption coefficient α k thus obtained is shown in FIG.
In this embodiment, the accuracy of the measuring device for the transmittance T and the reflectance R is:
Since it is about ± 3%, the light absorption coefficient was measured in the range of 3% <T / (1-R) <97%, that is, in the range of about 550 nm to 770 nm. In the examples described later, the measurement accuracy of the light absorption coefficient is determined not by the measurement method but by the accuracy of the measuring instrument used).
第４図は膜厚約0.1μｍのａ−SiC:Hの透過率Ｔ反射率
Ｒ及びT/（１−Ｒ）の波長に対する測定データを示す。
このデータをもとに、前記（１）式より得られた光吸収
係数αｋの波長に対する値を第５図に示す。この図から
明らかなように、波長約400nm〜550nmの範囲で光干渉に
よる影響を殆ど受けること無く光吸収係数が観測されて
いる。FIG. 4 shows the measurement data for the transmittance T, the reflectance R and the wavelength of T / (1-R) of a-SiC: H having a film thickness of about 0.1 μm.
Based on this data, FIG. 5 shows the values of the light absorption coefficient α k with respect to the wavelength obtained from the above equation (1). As is apparent from this figure, the light absorption coefficient is observed in the wavelength range of about 400 nm to 550 nm with almost no influence by light interference.
又第６図は膜厚約0.5μｍの透明電極であるITO（酸化
インジウム錫）の透過率Ｔ、反射率Ｒ及びT/（１−Ｒ）
の波長に対する測定データを示す。このデータをもと
に、前記（１）式より得られた光吸収係数αｋの波長に
対する値を第７図に示す。この図から明らかなように波
長約350nm〜2000nmの範囲で光吸収係数が光干渉の影響
を受けること無く観測されている。FIG. 6 shows the transmittance T, reflectance R and T / (1-R) of ITO (indium tin oxide), which is a transparent electrode having a thickness of about 0.5 μm.
3 shows measurement data for the wavelengths of FIG. Based on this data, FIG. 7 shows the values of the light absorption coefficient α k obtained from the above equation (1) with respect to the wavelength. As is apparent from this figure, the light absorption coefficient is observed in the wavelength range of about 350 nm to 2000 nm without being affected by light interference.
（ト）発明の効果 以上の説明の如く本発明によれば光干渉が顕著な薄膜
の光吸収係数を精密に測定することができ例えば薄膜太
陽電池等の光学デバイス設計を精密に行うことが可能と
なる効果が生まれる。(G) Effects of the Invention As described above, according to the present invention, it is possible to precisely measure the light absorption coefficient of a thin film having remarkable light interference, and to precisely design an optical device such as a thin film solar cell. The effect which becomes becomes.
第１図は本発明装置の一実施例を示すブロック図、第２
図はａ−Si:Hの光干渉除去の例を示す図、第３図は第２
図の結果得られた光吸収係数を示す図第４図及び第５図
はａ−SiC:Hの場合のそれぞれ第２図及び第３図に相当
する図、第６図及び第７図はITOの場合のそれぞれ第２
図及び第３図に相当する図である。 （Ｄ）……検出器、（MC）……マイクロプロセッサ。FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention, and FIG.
The figure shows an example of optical interference removal of a-Si: H, and FIG.
FIGS. 4 and 5 show the light absorption coefficients obtained as a result of the drawing. FIGS. 4 and 5 correspond to FIGS. 2 and 3 in the case of a-SiC: H, respectively. FIGS. 6 and 7 show ITO. The second in the case of
FIG. 4 is a diagram corresponding to FIG. 3 and FIG. (D) Detector, (MC) Microprocessor.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中野 昭一 大阪府守口市京阪本通２丁目18番地 三 洋電機株式会社内 (56)参考文献 特開 昭63−225136（ＪＰ，Ａ) 特開 昭62−204104（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Shoichi Nakano 2-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-63-225136 (JP, A) JP-A Sho 62-204104 (JP, A)
Claims (1)
る検出器と、該検出器の光透過率Ｔ及び光反射率Ｒのデ
ータに基づいてT/（１−Ｒ）の演算を行いその演算結果
を用いて前記薄膜の光吸収係数を算出するマイクロプロ
セッサとより成ることを特徴とする光吸収係数の測定装
置。1. A detector for detecting a light transmittance T and a light reflectance R of a thin film, and T / (1-R) based on data of the light transmittance T and the light reflectance R of the detector. A light absorption coefficient measuring device, comprising: a microprocessor that performs an operation and calculates a light absorption coefficient of the thin film using the operation result.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8310389A JP2703324B2 (en) | 1989-03-31 | 1989-03-31 | Optical absorption coefficient measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8310389A JP2703324B2 (en) | 1989-03-31 | 1989-03-31 | Optical absorption coefficient measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02262037A JPH02262037A (en) | 1990-10-24 |
| JP2703324B2 true JP2703324B2 (en) | 1998-01-26 |
Family
ID=13792858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8310389A Expired - Fee Related JP2703324B2 (en) | 1989-03-31 | 1989-03-31 | Optical absorption coefficient measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2703324B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1468262A1 (en) * | 2002-01-17 | 2004-10-20 | Agilent Technologies, Inc. | Determination of optical properties of a device under test in both directions in transmission and in reflection |
| US20140176570A1 (en) * | 2012-12-21 | 2014-06-26 | Pixtronix, Inc. | Interferometric light absorbing structure for display apparatus |
-
1989
- 1989-03-31 JP JP8310389A patent/JP2703324B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02262037A (en) | 1990-10-24 |
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