Leybold Systems Gmbh

Leybold Aktiengesellschaft

Balzers Und Leybold

Joachim Aufreiter

Klaus Kalkowski

Burkhard Altekruger

Burkhard Altekr&uuml;ger

Dieter Bruss

Dieter Br&uuml;ss

Roland Gesche

Martin Flachsel

Burkhard Alterkruger

A device and process for the determination of the diameters of a crystal that is pulled from a liquified material. In this connection several video cameras are provided, each of which reproduces its own section along the vertical axis of the crystal or in a direction vertical to it. The image angles of the camera are laid out in such a way that the object to be reproduced completely fills the entire picture plane&mdash;at least in one direction. For objects with a small diameter; e.g., the crystal neck, a camera with a small image angle is used, while for objects with a large diameter; e.g., the crystal body, a camera with a large image angle is used.

Device and method for the determination of diameters of crystals

A crystal pulling unit for the production of a crystal block has a recharging tube (,), via which granulate (,) enters into a crucible (,) with a melt (,), located within a container (,). This recharging tube (,) has an annular space (,) between an inner wall (,) and an outer wall (,), which is open on the lower front side of the recharging tube (,) and is connected with the protective gas source (,) to supply protective gas. This protective gas cools the recharging tube (,) and around its outlet, forms a gas mist that prevents the entry of finer fractions of the charging material into the pulling space.

Crystal pulling unit

A crystal pulling unit for the production of a crystal block has a recharging tube (,), via which granulate (,) is introduced into a crucible (,) with a melt (,), located inside a container (,). A fine-dust separator (,) is located in the recharging tube (,) outside the container (,); the separator works like an air classifier and, by means of a protective gas cushion, removes fine dusts from the granulate (,). This counters the danger of clogging of the recharging tube (,) by the caking of the recharging material.

A device for monitoring a melt for the production of crystals. A camera is provided which images at least portions of the surface of the contents of a crucible. An evaluating device is used to evaluate the camera's images with respect to solid and liquid portions of the surface of the crucible contents.

Device and a process for monitoring a melt for the production of crystals

A device for controlling crystal growth processes which run through various process phases, for instance, melting or cool-down, and in which the shape of the crystal has different areas during growth, for instance, a neck and/or a shoulder. Certain process parameters and target values, as well as input values and output values, for instance, a certain gas pressure or a certain rotational speed, are also associated with each of these areas and phases. The linking of these parameters is accomplished by function generators or tables. With the aid of the control device, it is made possible to generate a specially adapted linking of the respectively necessary input and output parameters for each of the special process phases and crystal sections with an essentially uniform construction and a comprehensible structure. This permits an optimized process operation with high reproducibility, in which manual interventions by the operating personnel during the entire process and also during the transition phases between different process steps are not necessary.

Device for controlling crystal growth processes

An image of the meniscus ring (21) between the crystal (20) and the melt (4) is formed by optical means (12, 24) on a sensor, the signals of which yield the actual value for the diameter of the crystal. Two optical measuring devices are provided, the optical paths of which are defined by base points on the meniscus ring (21) and two planes which are offset by 90.degree. to each other and which are parallel to the main axis of the crystal and in tangential contact with the meniscus ring (21). The two optical paths are preferably set up to intersect, their intersection being in the viewing window.

Apparatus for drawing single crystals by the czochralski method

A source (1) is equipped with a conveying device (4) for discharging the particles (2, 2a) at adjustable rates per unit time. A crystal (16), formed from doped particles, is withdrawn from the melting crucible (13) at a predetermined rate per unit time. So that the control process can be conducted smoothly over prolonged periods of time with precise doping, the particles (2, 2a) are fed single file to the melting crucible (13) and counted by at least one sensor (21, 22). The sequence of count pulses is sent to a counter (25) and compared there with a corresponding sequence of reference input pulses. The comparison signal formed from the count pulses and the reference input pulses is used, in accordance with its sign, as a control signal for adjusting the amount of particles being discharged per unit time from source (1) to correspond to the reference value.

Controlled feeding Czochralski apparatus

In a process and a device for the controlled feeding of a melting crucible (13) with doped particles (2, 2a) during the drawing of a crystal (16) by the Czochralski method by the control of a flow of particles (2, 2a) from a source (1) to the melting crucible (13), the source (1) is equipped with a conveying device (4) for discharging the particles (2, 2a) at adjustable rates per unit time. A crystal (16), formed from the particles, is withdrawn from the melting crucible (13) at a predetermined rate per unit time. So that the control process can be conducted smoothly over prolonged periods of time with precise doping, the particles (2, 2a) are separated into individuals on their way to the melting crucible (13) and counted by at least one sensor (21, 22). The sequence of count pulses is sent to a counter (25) and compared there with a corresponding sequence of reference input pulses. The comparison signal formed from the count pulses and the reference input pulses is used, in accordance with its sign, as a control signal for adjusting the amount of particles being discharged per unit time from source (1) to correspond to the reference value.

Process for the controlled feeding of a melting crucible with particles

A crucible is situated in a vacuum chamber and provided with a feeder for granulate material, heating elements for melting the material, and a crystal puller above the crucible. Measuring elements provide signals for a controller including a fuzzy processor utilizing an empirically determined data field to output a signal for the material feeder.

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Alzenau, Germany

Joachim Aufreiter