Leybold Systems Gmbh

Leybold Aktiengesellschaft

Klaus Kalkowski

Joachim Aufreiter

Dieter Bruss

Burkhard Altekruger

Burkhard Altekr&uuml;ger

Dieter Br&uuml;ss

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 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

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.

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Gründau, Germany

Klaus Kalkowski