JPH0158454B2 - - Google Patents
Info
- Publication number
- JPH0158454B2 JPH0158454B2 JP59130616A JP13061684A JPH0158454B2 JP H0158454 B2 JPH0158454 B2 JP H0158454B2 JP 59130616 A JP59130616 A JP 59130616A JP 13061684 A JP13061684 A JP 13061684A JP H0158454 B2 JPH0158454 B2 JP H0158454B2
- Authority
- JP
- Japan
- Prior art keywords
- photoluminescence
- wafer
- sample
- light
- excitation laser
- 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
- 238000005424 photoluminescence Methods 0.000 claims description 42
- 230000003287 optical effect Effects 0.000 claims description 28
- 230000005284 excitation Effects 0.000 claims description 22
- 235000012431 wafers Nutrition 0.000 claims description 17
- 239000004065 semiconductor Substances 0.000 claims description 10
- 238000010521 absorption reaction Methods 0.000 claims description 5
- 238000004458 analytical method Methods 0.000 claims description 5
- 230000000644 propagated effect Effects 0.000 claims 1
- 238000000034 method Methods 0.000 description 11
- 239000013078 crystal Substances 0.000 description 10
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 9
- 230000007547 defect Effects 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 238000007796 conventional method Methods 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- 230000004075 alteration Effects 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 238000004020 luminiscence type Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000009828 non-uniform distribution Methods 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- MUJOIMFVNIBMKC-UHFFFAOYSA-N fludioxonil Chemical compound C=12OC(F)(F)OC2=CC=CC=1C1=CNC=C1C#N MUJOIMFVNIBMKC-UHFFFAOYSA-N 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000000103 photoluminescence spectrum Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6489—Photoluminescence of semiconductors
Landscapes
- Health & Medical Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Description
【発明の詳細な説明】
〔技術分野〕
本発明は、半導体の結晶の微小領域に光を照射
して励起したフオトルミネツセンスの観測によ
り、半導体結晶中の微小領域における不純物や欠
陥等を評価する顕微フオトルミネツセンス法を用
いた光学測定装置に関するものである。[Detailed Description of the Invention] [Technical Field] The present invention is a method for evaluating impurities, defects, etc. in a micro region in a semiconductor crystal by observing photoluminescence excited by irradiating the micro region of the semiconductor crystal with light. This invention relates to an optical measuring device using a microscopic photoluminescence method.
〔従来技術〕
各種の電子デバイスに広く使用されているSi、
GaAs、GaP等の半導体結晶中に存在する不純物
や欠陥は、デバイス特性に大きな影響を与える。
最近では、デバイス高集積化・高品質化が進み、
素材結晶中の微少領域の不純物や欠陥の分布状態
が問題となつてきている。特に、超LSI用CZ−Si
（回転引き上げSi）結晶中の酸素析出物や高速IC
用の半絶縁性GaAs結晶中のアンチサイト欠陥な
どのように、深い準位を形成する微少欠陥のウエ
ーハ面内不均一分布が重要視されている。このよ
うな深い準位を形成する微小欠陥の不均一分布を
調べるには、高感度で微小領域の測定が原理的に
可能であるフオトルミネツセンス法がきわめて有
力であり、このフオトルミネツセンス法について
はこれまでにいくつかの報告例があるが、以下に
示すような欠点のために十分な評価が行なわれて
いなかつた。[Prior art] Si, which is widely used in various electronic devices,
Impurities and defects present in semiconductor crystals such as GaAs and GaP have a significant impact on device characteristics.
Recently, devices have become more highly integrated and of higher quality.
The distribution of impurities and defects in minute regions in material crystals has become a problem. In particular, CZ-Si for super LSI
(Rotation-pulled Si) Oxygen precipitates in crystals and high-speed IC
The non-uniform distribution within the wafer surface of minute defects that form deep levels, such as anti-site defects in semi-insulating GaAs crystals for industrial applications, is becoming important. The photoluminescence method is extremely effective in investigating the uneven distribution of microscopic defects that form such deep levels, as it is in principle possible to measure microscopic regions with high sensitivity. Although there have been several reports on this method, it has not been fully evaluated due to the following shortcomings.
従来、上述のフオトルミネツセンス法による微
小領域のフオトルミネツセンス観測を行なう際に
用いられていた顕微測定光学系の概略構成例を第
１図および第２図に示す。 FIGS. 1 and 2 show examples of a schematic configuration of a microscopic measurement optical system conventionally used for photoluminescence observation of a minute area by the above-mentioned photoluminescence method.
第１図に示す光学系は通常の光学顕微鏡を用い
て励起光の照射およびフオトルミネツセンス光の
集光を行なう方式のものである。この励起光とし
ては、半導体試料の禁制帯幅よりも大きいエネル
ギーをもつ高い輝度の光が必要であることから、
例えばArレーザー光またはHe−Neレーザー光
などが用いられている。すなわち、試料１の上方
に設置された顕微鏡２の側方からレーザー光３を
入射させ、このレーザー光３を半透鏡４によつて
顕微鏡内の下方に導き、さらに対物レンズ５によ
つて絞り込み、試料１の表面に照射する。同時
に、顕微鏡２の通常の機能として、接眼レンズ６
によつて試料１の表面を高倍率で観察することが
できる。なお、一般に試料１は冷却容器内に入れ
られ、液体窒素または液体ヘリウム温度に冷却さ
れている。 The optical system shown in FIG. 1 uses an ordinary optical microscope to irradiate excitation light and collect photoluminescence light. This excitation light requires high brightness light with energy greater than the forbidden band width of the semiconductor sample.
For example, Ar laser light or He-Ne laser light is used. That is, a laser beam 3 is incident from the side of a microscope 2 placed above a sample 1, guided downward into the microscope by a semi-transparent mirror 4, and further narrowed down by an objective lens 5. Irradiate the surface of sample 1. At the same time, as a normal function of the microscope 2, the eyepiece 6
This allows the surface of sample 1 to be observed at high magnification. Note that the sample 1 is generally placed in a cooling container and cooled to the temperature of liquid nitrogen or liquid helium.
さて、試料１の表面のレーザー光３で照射され
たところから発せられるフオトルミネツセンス光
は、同一の対物レンズ５によつて集光され、光路
中に挿入された反射鏡７により分光器９に導か
れ、分光器により、分光特性が調べられる。ここ
で、入射レザー光３の試料表面での反射光もフオ
トルミネツセンス光と同一の経路で分光器に達す
るので、この反射光をフオトルミネツセンス光か
ら分離するフイルター８が必要となる。 Now, the photoluminescence light emitted from the surface of the sample 1 irradiated with the laser beam 3 is focused by the same objective lens 5, and is passed through the spectroscope 9 by the reflecting mirror 7 inserted in the optical path. The spectral characteristics are examined using a spectrometer. Here, since the reflected light of the incident laser light 3 on the sample surface also reaches the spectroscope along the same path as the photoluminescence light, a filter 8 is required to separate this reflected light from the photoluminescence light.
このような従来方式では、レーザー光照射およ
び試料観察に関しては問題はないが、フオトルミ
ネツセンス集光に関し、通常仕様の対物レンズを
使用している点で問題がある。すなわち、通常の
対物レンズは可視光領域で使用することを念頭
に、波長4400〜800nｍの範囲で色収差等の収差
を補正するように設計されているので、800nｍ
以上の波長領域では収差が急激に増大するととも
に、レンズ材質やコーテイング材質の関係で透過
特性も著しく悪くなつてしまう。したがつて、
1μｍ以上の波長となるGaAsおよびGaPの深い準
位やSiのフオトルミネツセンスの測定は行なえな
くなつてしまう。また、波長の短かい領域におい
ても、微弱なフオトルミネツセンス光に対して数
桁以上の強度の励起用のレーザー光が混入するの
で、フイルターの螢光等の困難な問題が発生す
る。 In such a conventional method, there is no problem with respect to laser beam irradiation and sample observation, but there is a problem with respect to photoluminescence condensation in that a standard objective lens is used. In other words, normal objective lenses are designed to correct aberrations such as chromatic aberration in the wavelength range of 4400 to 800 nm, with the intention of using them in the visible light range.
In the above wavelength range, aberrations increase rapidly and transmission characteristics also deteriorate significantly due to the lens material and coating material. Therefore,
It becomes impossible to measure the deep levels of GaAs and GaP and the photoluminescence of Si at wavelengths of 1 μm or more. Furthermore, even in a short wavelength region, excitation laser light with an intensity of several orders of magnitude or more is mixed with the weak photoluminescence light, causing difficult problems such as fluorescence in the filter.
以上の点から、この従来方式は、GaAsおよび
GaPにおける禁制帯幅付近の光エネルギーの強い
フオトルミネツセンスに対してはきわめて有効で
あり、冷却容器内にセツトした試料面上にレーザ
ー光を直径約1μｍに絞り込んで照射することに
よつて非常に高い空間的分解能のフオトルミネツ
センス分析が得られる旨の成功例が報告されてい
るが、深い準位のルミネツセンスに対しては全く
無力であつた。 From the above points, this conventional method is suitable for GaAs and
It is extremely effective for photoluminescence with strong optical energy near the forbidden band width in GaP, and it is extremely effective for irradiating the sample surface set in a cooling container with laser light focused to a diameter of approximately 1 μm. Successful examples have been reported in which photoluminescence analysis with high spatial resolution can be obtained, but it was completely powerless against deep level luminescence.
これに対し、第２図に示す光学系による方式で
は、励起用レーザー光学系とフオトルミネツセン
ス集光系を分離することによつて上述の欠点を除
去している。すなわち、試料１の表面の上方に二
系統の光学系を配置し、レーザー光３の照射には
通常の対物レンズ５を用い、フオトルミネツセン
ス光の集光には長い波長領域が測定をも可能にす
る石英レンズ光学系１０（あるいは球面反射鏡光
学系）を用いている。ところが、一般にフオトル
ミネツセンス光は微弱であるので、その集光系１
０をレーザー照射系５に優先して考える必要があ
ることから、レーザー照射系５は第２図に示すよ
うにフオトルミネツセンス集光光路を防げないよ
うに側方に設置しなければならなくなり、対物レ
ンズ５から試料１までの距離（動作距離）は長く
なる。したがつて、この対物レンズ５として高倍
率の対物レンズは使用できず、レーザー光の絞り
込みは甘くなる。この方式によるこれまでの報告
例では、試料を冷却容器内に入れた場合に、最小
ビーム径はたかだか50μｍ程度にしかならない。
また、試料表面観察も斜め入射のためにぼけた像
になつてしまうという欠点があつた。 On the other hand, in the system using the optical system shown in FIG. 2, the above-mentioned drawbacks are eliminated by separating the excitation laser optical system and the photoluminescence focusing system. That is, two optical systems are arranged above the surface of the sample 1, a normal objective lens 5 is used for irradiation of the laser beam 3, and a long wavelength region is used for focusing the photoluminescence light. A quartz lens optical system 10 (or a spherical reflecting mirror optical system) is used to make this possible. However, since photoluminescence light is generally weak, the light collection system 1
Since it is necessary to consider 0 in priority over the laser irradiation system 5, the laser irradiation system 5 must be installed on the side so as not to block the photoluminescence condensing optical path, as shown in Figure 2. , the distance from the objective lens 5 to the sample 1 (operating distance) becomes longer. Therefore, an objective lens with high magnification cannot be used as the objective lens 5, and the narrowing down of the laser beam becomes difficult. In the examples reported so far using this method, the minimum beam diameter is only about 50 μm at most when the sample is placed in a cooling container.
In addition, observation of the sample surface also had the disadvantage of resulting in a blurred image due to oblique incidence.
このように、顕微フオトルミネツセンス法は原
理的には極微小領域の不純物や欠陥の高感度評価
が可能であるが、実際には従来の手法を使用する
限り、長波長領域のフオトルミネツセンスを示す
深い準位などの評価は適用できず、大きな問題と
されていた。 In this way, the microscopic photoluminescence method is theoretically capable of highly sensitive evaluation of impurities and defects in extremely small areas, but in reality, as long as conventional methods are used, photoluminescence in the long wavelength region cannot be detected. Evaluations such as deep levels that indicate sense could not be applied, and this was considered a major problem.
本発明の目的は、上述した従来の顕微フオトル
ミネツセンス法による光学測定装置の欠点を除去
し、試料を高倍率で顕微鏡観察可能にすると同時
に、励起用レーザー光を極微小領域に照射し、試
料から発せられたフオトルミネツセンスに対して
広い波長領域にわたつて分光析を行なうことがで
きるようにした光学測定装置を提供することにあ
る。
The purpose of the present invention is to eliminate the drawbacks of the optical measuring device using the conventional microscopic photoluminescence method described above, to enable a sample to be observed under a microscope at high magnification, and at the same time to irradiate an extremely small area with excitation laser light. It is an object of the present invention to provide an optical measuring device capable of performing spectroscopic analysis of photoluminescence emitted from a sample over a wide wavelength range.
すなわち、本発明の光学測定装置においては、
半導体試料表面の極微小領域に励起レーザー光を
照射し、励起レーザー光を半導体の基礎吸収機構
（禁制帯間還移機構）によつて試料内で完全に吸
収させ、試料内で発生させたフオトルミネツセン
スのうちで試料を透過した成分を試料の裏面より
効率良く集光することを特徴とするものである。
That is, in the optical measurement device of the present invention,
A microscopic region on the surface of a semiconductor sample is irradiated with excitation laser light, and the excitation laser light is completely absorbed within the sample by the basic absorption mechanism (forbidden band reduction mechanism) of the semiconductor, resulting in a photo generated within the sample. It is characterized by the fact that the components of the luminescence that have passed through the sample are efficiently focused from the back surface of the sample.
以下に、図面を参照して、本発明を詳細に説明
する。第３図は本発明の一実施例を示し、試料１
に励起用レーザー光を照射する部分については、
前述の第１図に示した従来例と同様な構成の光学
系を使用するものとする。すなわち、試料１上に
設置された顕微鏡２の側方から励起用レーザー光
３を入射させ、このレーザー光３を半透鏡４によ
つて顕微鏡光路２内の下方に導き、さらに対物レ
ンズ５によつて絞り込み、試料１の表面に照射す
る。同時に、接眼レンズ６によつて試料１の表面
を高倍率で観察する。このとき、試料１の照射さ
れた極微小領域部分から発せられるフオトルミネ
ツセンス光の角度方向の強度分布は試料１の上下
方向に対して等方的と考えて良い。また、その光
エネルギーは試料１からの禁制帯幅よりも小さい
エネルギーである。したがつて、フオトルミネツ
センス光の半分は、レーザー光照射と同じ側の試
料１の表面から放射され、その残りは試料１内を
下方に伝播してその裏面から放射される。
The present invention will be described in detail below with reference to the drawings. FIG. 3 shows an embodiment of the present invention, in which sample 1
For the part where the excitation laser light is irradiated,
It is assumed that an optical system having a configuration similar to that of the conventional example shown in FIG. 1 described above is used. That is, an excitation laser beam 3 is incident from the side of a microscope 2 placed on a sample 1, and this laser beam 3 is guided downward into the microscope optical path 2 by a semi-transparent mirror 4, and then guided by an objective lens 5. The surface of sample 1 is irradiated. At the same time, the surface of the sample 1 is observed at high magnification through the eyepiece 6. At this time, the intensity distribution in the angular direction of the photoluminescence light emitted from the irradiated extremely small area of the sample 1 can be considered to be isotropic with respect to the vertical direction of the sample 1. Further, the light energy is smaller than the forbidden band width from the sample 1. Therefore, half of the photoluminescence light is emitted from the surface of the sample 1 on the same side as the laser beam irradiation, and the remainder propagates downward within the sample 1 and is emitted from the back surface thereof.
また、
測定対象としている試料１は電子デバイス作
製用のウエーハが主であり、その厚さは数
100μｍ程度の薄い試料であること、
特に測定で着目したいフオトルミネツセンス
は深い準位からのものであつて、禁制帯幅エネ
ルギーよりもはるかに小さいエネルギーの光で
あること、
以上の理由により、試料１内の伝播中でのフオ
トルミネツセンス光の吸収は少なく、実際上ほと
んど無視できる。したがつて、本図に示すように
広い波長領域に対応できる石英レンズのような集
光レンズ系１０（あるいは反射鏡型集光系）を試
料１の裏面側に設置することによつて、レーザー
光３の照射点より発せられるフオトルミネツセン
ス光を高効率で集光し、フイルター８を通して分
光器９に導くことができる。 In addition, sample 1, which is the measurement target, is mainly a wafer used for manufacturing electronic devices, and its thickness is several degrees.
For the above reasons, the sample is about 100 μm thin, and the photoluminescence that we want to focus on in the measurement comes from a deep level and has an energy much smaller than the forbidden band energy. The absorption of photoluminescence light during propagation within the sample 1 is small and can be virtually ignored. Therefore, as shown in this figure, by installing a condensing lens system 10 such as a quartz lens (or a reflecting mirror type condensing system) capable of handling a wide wavelength range on the back side of the sample 1, the laser The photoluminescence light emitted from the irradiation point of the light 3 can be collected with high efficiency and guided to the spectroscope 9 through the filter 8.
一般に、禁制帯幅エネルギーよりも大きいエネ
ルギーの光に対しては、半導体の基礎吸収機構に
より試料の光吸収係数は104〜105cm-1と非常に大
きい。したがつて、禁制帯幅よりも大きいエネル
ギー有する励起レーザー光３は薄いウエーハ状の
試料１においても極めて大きく吸収される。例え
ば、Siウエーハに対し励起レーザー光としてAr
レーザーの青色線（波長（488nｍ）を用いた場
合の吸収係数は約104cm-1以上であり、ウエーハ
の厚さが通常の規格の厚さμｍ程度であるとする
と、励起レーザー光のウエーハ内透過率は10-200
以下の値となり、事実上零と見倣すことができ
る。したがつて、従来の第１図および第２図に示
した従来方式で問題となつた励起用レーザー光の
フオトルミネツセンス光への混入はほとんど問題
とならない。 Generally, for light with energy greater than the forbidden band energy, the light absorption coefficient of the sample is extremely large, 10 4 to 10 5 cm -1, due to the basic absorption mechanism of semiconductors. Therefore, the excitation laser beam 3 having an energy larger than the forbidden band width is extremely strongly absorbed even in the thin wafer-shaped sample 1. For example, Ar is used as an excitation laser beam for Si wafers.
The absorption coefficient when using the blue line (wavelength (488 nm)) of the laser is approximately 10 4 cm -1 or more, and assuming that the wafer thickness is about the standard thickness of μm, the wafer of the excitation laser beam Internal transmittance is 10 -200
The value is as follows, which can be virtually considered as zero. Therefore, the mixing of the excitation laser light into the photoluminescence light, which was a problem in the conventional methods shown in FIGS. 1 and 2, is hardly a problem.
次に、第３図の本発明装置を用いて、実際に測
定した結果を示す。 Next, results actually measured using the apparatus of the present invention shown in FIG. 3 will be shown.
第４図は、一例として高速ICに用いられる無
添加半絶縁性引き上げGaAsウエーハを第３図の
試料１として用いた場合に、このウエーハの転位
線近傍のフオトルミネツセンス光の光強度変化の
状態を転位線からの距離（単位、μｍ）で示した
ものである。この試料１は液体ヘリウム温度に冷
却し、第３図に示す配置状態で試料１に紙面に垂
直な方向に移動させてフオトルミネツセンス強度
の一次元分布の変化を分光器９により測定した。
また、対物レンズ５としては長動作距離の５倍の
レンズを用い、波長514nｍのArレーザー光３を
直径20μｍまで絞り込むことができた。上述の
GaAs結晶のフオトルミネツセンス・スペクトル
は、残留炭素不純物による1.49eV（832nｍ）の発
光帯と、EL2と呼ばれる深い準位に起因すると考
えられる0.65eV（1.9μｍ）の発光帯とから成つて
いる。 Figure 4 shows, as an example, when an undoped semi-insulating pulled GaAs wafer used in high-speed ICs is used as sample 1 in Figure 3, the change in the light intensity of photoluminescence light near the dislocation lines of this wafer is shown. The state is shown in terms of distance (unit: μm) from the dislocation line. This sample 1 was cooled to liquid helium temperature, and the sample 1 was moved in a direction perpendicular to the plane of the paper in the arrangement shown in FIG. 3, and changes in the one-dimensional distribution of photoluminescence intensity were measured using a spectrometer 9.
Further, by using a lens with a long working distance of 5 times as the objective lens 5, it was possible to narrow down the Ar laser beam 3 with a wavelength of 514 nm to a diameter of 20 μm. mentioned above
The photoluminescence spectrum of GaAs crystals consists of a 1.49 eV (832 nm) emission band due to residual carbon impurities and a 0.65 eV (1.9 μm) emission band thought to be caused by a deep level called EL2. .
1.49eVの発光帯の強度分布は、第４図の波形
ａに示すように、転位のとろ（０で示す）で急激
にその強度が減少し、その外側の50μｍ程度まで
離れたところでは転位からさらに遠く離れたとこ
ろよりも強度が強くなつている。これは、従来の
手法により報告されている結果と一致する。 As shown in waveform a in Figure 4, the intensity distribution of the 1.49 eV emission band decreases rapidly at the point of the dislocation (indicated by 0), and at a distance of about 50 μm outside of the point, the intensity decreases from the dislocation. It is even stronger than it is at a distance. This is consistent with results reported by conventional techniques.
一方、0.65eVの発光帯に対しては、高い空間
的分解能で測定した例はこれまでに報告がなかつ
たが、第３図示の本発明装置によれば上述のよう
に励起レーザー光３を直経20μｍに絞り込んで測
定することができるので、その結果、第４図の波
形ｂに示すように、少くともこのGaAsウエーハ
の試料に関する限り0.65eVの発光帯の強度は転
位によつて影響を受けないことが明らかになつ
た。 On the other hand, for the 0.65 eV emission band, there have been no reports of measurement with high spatial resolution, but according to the apparatus of the present invention shown in Figure 3, the excitation laser beam 3 can be directly transmitted as described above. As a result, as shown in waveform b in Figure 4, the intensity of the 0.65 eV emission band is affected by dislocations, at least as far as this GaAs wafer sample is concerned. It became clear that there was no.
以上の測定結果は予備的実験によるものであ
り、試料の低温容器が大型であつたのでレーザー
光の絞り込みがあまり良くなかつたが、現在、低
温容器に関して小型化するとともに、光学窓にサ
フアイヤを用い、励起光学系に無限焦点の20倍の
高性能対物レンズが使用できるように改良してい
る。これにより、励起用レーザー光は直径2μｍ
程度にまで絞り込むことができると推定され、さ
らにフオトルミネツセンス集光系には反射鏡型集
光光学系を用いることによつて、可視光から5μ
ｍ適度までの広い波長領域の極微小領域のフオト
ルミネツセンス分析が可能になると期待される。 The above measurement results are based on preliminary experiments, and because the sample cryogenic container was large, the focus of the laser beam was not very good.However, the cryogenic container is now smaller and saphire is used for the optical window. The excitation optical system has been improved to allow the use of a 20x afocal high-performance objective lens. As a result, the excitation laser beam has a diameter of 2 μm.
Furthermore, by using a reflective mirror-type focusing optical system for the photoluminescence focusing system, it is possible to narrow down the visible light to 5 μm.
It is expected that photoluminescence analysis will become possible in a very small wavelength range up to a moderate wavelength range.
以上から明らかなように、本発明の光学測定装
置を用いることにより、各種デバイス作製に用い
られるSi、GaAs、GaPのウエーハのフオトルミ
ネツセンスを広い波長領域にわたつて数μｍ程度
の高い空間的分解能で測定することが可能とな
る。これは、従来の手法では全く行なえなかつた
ものである。
As is clear from the above, by using the optical measurement device of the present invention, the photoluminescence of Si, GaAs, and GaP wafers used for manufacturing various devices can be measured over a wide wavelength range with a high spatial resolution of several μm. It becomes possible to measure with high resolution. This is something that could not be done using conventional methods.
さらに、本発明装置によれば、フオトルミネツ
センス測定において有害である励起用レーザー光
の混入を極めて少なくすることができるという格
別の効果も有している。 Furthermore, the apparatus of the present invention has the special effect of extremely reducing the amount of excitation laser light that is harmful to photoluminescence measurements.
また、本発明の光学測定装置を用いた顕備フオ
トルミネツセンス法は、半導体結晶中の転位や微
小析出物などと深い準位との関連性を調べて行く
上できわめて有用となるばかりでなく、結晶内で
の微小欠陥や不準物の微視的な不均一分布がデバ
イス特性に及ぼす影響の検討、さらには高集積度
デバイス中での微細素子の不良部分の解明などに
おいて大きく貢献するものと思われる。 In addition, the sensible photoluminescence method using the optical measuring device of the present invention will be extremely useful in investigating the relationship between deep levels and dislocations and microprecipitates in semiconductor crystals. This will greatly contribute to the study of the effects of microscopic defects and non-uniform distribution of impurities within crystals on device characteristics, as well as to the elucidation of defective parts of minute elements in highly integrated devices. It seems to be.
第１図および第２図はそれぞれ従来の光学測定
装置による顕微フオトルミネツセンス法の原理を
示す内部構成図、第３図は本発明光学装置による
顕微フオトルミネツセンス法の原理を示す内部構
成図、第４図はGaAs結晶の転位線近傍の1.49eV
発光帯および0.65eV発光帯の強度分布をそれぞ
れ示す特性曲線図である。
１……試料、２……光学顕微鏡、３……励起用
レーザー、４……半透鏡、５……対物レンズ、６
……接眼レンズ、７……反射鏡、８……フイルタ
ー、９……分光器、１０……集光レンズ。
1 and 2 are internal configuration diagrams showing the principle of the microscopic photoluminescence method using a conventional optical measuring device, respectively, and FIG. 3 is an internal configuration diagram showing the principle of the microscopic photoluminescence method using the optical device of the present invention. Figure 4 shows 1.49eV near the dislocation line of GaAs crystal.
FIG. 3 is a characteristic curve diagram showing the intensity distribution of the emission band and the 0.65 eV emission band, respectively. 1...Sample, 2...Optical microscope, 3...Excitation laser, 4...Semi-transparent mirror, 5...Objective lens, 6
...Eyepiece, 7...Reflector, 8...Filter, 9...Spectroscope, 10...Condensing lens.
Claims (1)
ウエーハのフオトルミネツセンス分析を行なう際
に、通常の顕微鏡光学系を用いて前記ウエーハの
表面観察を行ないながら前記フオトルミネツセン
ス分析をすべき前記ウエーハの場所を狙つて励起
用レーザー光を前記場所の極微小領域に絞り込ん
で照射し、励起用レーザー光を半導体ウエーハの
基礎吸収機構によりウエーハ内で完全に吸収せし
め、該照射した点から発せられて当該ウエーハ内
を伝播して該ウエーハの裏面に出射したフオトル
ミネツセンス光を該ウエーハの裏面に配置した集
光光学系により集光して分光器に導くことによ
り、前記励起用レーザー光と前記フオトルミネツ
センス光を完全に分離させて広範囲の波長領域に
わたる極微小領域のフオトルミネツセンス分析を
行なうようにしたことを特徴とする光学測定装
置。1. When performing photoluminescence analysis of semiconductor wafers used in various electronic devices, the wafer to be subjected to photoluminescence analysis while observing the surface of the wafer using an ordinary microscope optical system. The excitation laser beam is focused and irradiated on a very small area of the said place, and the excitation laser beam is completely absorbed within the wafer by the basic absorption mechanism of the semiconductor wafer, and the excitation laser beam is emitted from the irradiated point. The photoluminescence light propagated within the wafer and emitted to the back surface of the wafer is focused by a condensing optical system disposed on the back surface of the wafer and guided to a spectrometer, thereby combining the excitation laser light and the 1. An optical measuring device characterized in that photoluminescence light is completely separated to perform photoluminescence analysis in an extremely small region over a wide range of wavelength regions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13061684A JPS618649A (en) | 1984-06-25 | 1984-06-25 | Optical measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13061684A JPS618649A (en) | 1984-06-25 | 1984-06-25 | Optical measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS618649A JPS618649A (en) | 1986-01-16 |
| JPH0158454B2 true JPH0158454B2 (en) | 1989-12-12 |
Family
ID=15038478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13061684A Granted JPS618649A (en) | 1984-06-25 | 1984-06-25 | Optical measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS618649A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990001692A2 (en) * | 1988-07-29 | 1990-02-22 | Edinburgh Instruments Ltd. | Electro-optical measuring instruments |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5788348A (en) * | 1980-11-21 | 1982-06-02 | Hitachi Ltd | Method and device for spectral fluorescence |
-
1984
- 1984-06-25 JP JP13061684A patent/JPS618649A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5788348A (en) * | 1980-11-21 | 1982-06-02 | Hitachi Ltd | Method and device for spectral fluorescence |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS618649A (en) | 1986-01-16 |
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