SU968595A1

SU968595A1 - Method of determining semiconductor crystal shape

Info

Publication number: SU968595A1
Application number: SU802983427A
Authority: SU
Inventors: Артур Петрович Медвидь; Айгар Ольгертович Миезитис; Ян Янович Берзинь; Модест Геронимович Арман
Original assignee: Рижский Ордена Трудового Красного Знамени Политехнический Институт
Priority date: 1980-09-23
Filing date: 1980-09-23
Publication date: 1982-10-23

Description

(54) СПОСОБ ОПРЕДЕЛЕНИЯ ФОРМЫ ПОЛУПРОВОДНИКОВОГО(54) METHOD FOR DETERMINING THE FORM OF A SEMICONDUCTOR

КРИСТАЛЛАCRYSTAL

.Изобретение относитс к неразруШсОощему контролю и может быть использовано при производстве полупроводниковых кристаллов. .The invention relates to non-destructive testing and can be used in the manufacture of semiconductor crystals. .

Известен способ определени кристалла, заключающийс в том,, что на исследуемый образец воздействуют ультразвуковыми колебани ми под разными углами и затем по спектру отраженных сигналов оценивают форму инородного тела в однородной среде 1.The known method of determining a crystal is that the sample under study is affected by ultrasonic vibrations from different angles and then the shape of the foreign body in a homogeneous medium 1 is estimated from the spectrum of the reflected signals.

Недостатком известнбго способа вл етс то, что при близких значени х плотностей включений и однород ной среды отрахсенный сигнал будет слабо различим на уровне помех, что приводит к неточност м определени формы кристаллов.A disadvantage of the known method is that at close values of the density of inclusions and a homogeneous medium, the insured signal will be poorly distinguishable at the level of interference, which leads to inaccuracies in determining the shape of crystals.

Наиболее близким по технической су1цности к изобретению вл етс способ определени формы полупроводникового кристалла путем воздействи на него переменным ма нитным полем, йозбуждают в полупровЪдниковом материале вихревые токи и анализируют полученный сигнал 2.The closest in terms of technical significance to the invention is a method for determining the shape of a semiconductor crystal by acting on it with a variable magnetic field, stimulating eddy currents in a semiconductor material, and analyzing the received signal 2.

Однако известным способом не- возможно точно определить форму монокристалла так как вихревые токиHowever, it is not possible in a known manner to accurately determine the shape of a single crystal, since the eddy currents

навод тс как в монокристаллической так и в поликрйсталлической среде и измер етс их среднее значение. Целью изобретени вл етс определение формы монокристаллического кристалла, наход щегос в поликристаллической среде.are induced both in monocrystalline and in polycrystalline medium and their mean value is measured. The aim of the invention is to determine the shape of a single crystal crystal in a polycrystalline medium.

Поставленна цель достигаетс тем, что согласно способу определе10 ни форма полупроводникового .кристалла путем воздействи на него магнитным полем с последующим анализом полученного сигнала, дл воздействи на образец используют посто н15 ное магнитное поле, дополнительно образец размещают в электростатическом поле, направление которого пёр.пендикул рно к направлению вектора, напр женности магнитного тюл , пово20 рачивают кристалл вокруг оси, параллельной направлению вектора напр женности электростатического пол на 360, получгиот-зависимость силы тока от угла поворота кристалла иThe goal is achieved by the method of determining the shape of a semiconductor crystal by exposing it to a magnetic field and then analyzing the received signal, to influence a sample using a constant magnetic field, the sample is additionally placed in an electrostatic field whose direction is perpendicular to the direction of the vector, the intensity of the magnetic tul, rotate the crystal around an axis parallel to the direction of the vector of the intensity of the electrostatic field by 360 Iot-dependence of current strength on the angle of rotation of the crystal and

Claims

25, the shape of the crystal is determined by it. FIG. 1 shows a block diagram of a device for implementing this method in FIG. 2, an implementation of a method for determining the shape of a semiconductor crystal according to the current intensity 3 versus angle of rotation for a crystal having the shape of a rectangular prism; Figure 3 - the same for a crystal having the shape of a rectangular parallelepiped. A device for implementing the proposed method consists of an electrical voltage source 1, the voltage from which is applied to a semiconductor crystal 2 equipped with two ohmic contacts 3 and 4. A crystal is placed between poles 5 and a permanent magnet. The signal from semiconductor crystal 2 is fed to recording unit 7, which can be, for example, an oscilloscope. The second output of the recording unit 7 is connected to the output of the electrical supply source 1. The method is implemented as follows. The source 1 of the electric naphxen excites an electric current in a semiconductor crystal with noMOBtbio Ohmic contacts 3 and 4 whose diameter is less than the dimensions of single crystals. At the same time, the sample is placed between the poles 5 and 6 of the permanent magnet. Sample 2 is then rotated around the axis, parallel to the intensity of the magnetic field. The voltage across the crystal is recorded by the registration unit 7. In the case of a magnetoconcentration effect in weak magnetic fields, the effect is maximal, when the thickness of the single crystal crystal under study d with intrinsic conductivity is equal to the bipolar diffusion length L of this substance. In this case, the resistance of the sample in an external magnetic field is minimal. With increasing or decreasing thickness of the crystal, the resistance of the age of em. Because polycrystalline. Since the medium makes a small contribution to the current intensity versus rotation angle, this diagram gives us an idea of the shape of a single crystal crystal in a polycrystalline medium. The implementation of the method for specific crystals is shown in FIG. 2 and 3. They show in polar coordinates of the current strength versus angle of rotation diagram. The straight lines connecting the adjacent maxima in the diagram give the cross section of the crystal. The circles on and 3 are current diagrams of the angle of rotation of the crystal in the absence of a constant magnetic field. When implementing the proposed method, the linear dimensions of the crystal can be determined in the following ways. By knowing the resistivity of the sample under study and the length of 4 μ-crystals, the area can be determined. The sample cross section, knowing the shape of a single crystal, can also determine the length of all crystal faces. From the hodograms of the samples, it is possible to determine the size of the crystal, the shape of which has no center of inversion; Where the minima and maxima are obtained on the hodograph, the crystal size is approximately equal to the diffusion length. Easier and more accurate to determine the size of the first way. The method allows one to determine the shape of a single crystal in a polycrystalline medium. The invention of the Method. Determining the shape of a semiconductor crystal by exposing it to a magnetic field, followed by analyzing the received signal, is so that in order to determine the shape of a single crystal in a polycrystalline medium, effects on the sample use a constant magnetic field, additionally the sample is placed in an electrostatic field, the direction of which is perpendicular to the direction of the magnetic field strength vector, the crystal is rotated a circle of an axis parallel to the direction of the intensity vector of the electrostatic field through 360 °, the current is a function of the angle of rotation of the crystal, and the shape of the crystal is determined from it. Sources of information taken into account in the examination 1. Methods of non-destructive testing. Ed. R, Sharpe. M., Mir, 1972, p. 82-83. -

2. Yagudin G.Kh., Shibaev L.L., Ponomarenko O.N. Non-contact methods of non-destructive testing of the electrophysical parameters of semiconductor structures. Central Research Institute of Electronics, Moscow, 1973 (prototype).