Siltronic Ag

Wacker-Chemitronic Gesellschaft Fur Elektronik-Grundstoffe Mbh

Manfred Grundner

Peter John

Laszlo Fabry

Janis Virbulis

Wilfried Von Ammon

Ludwig Altmannshofer

Susanne Bauer-Mayer

Dieter Graef

Wolfgang Feichtner

Dieter Graefg

Rosemarie Winklharrer

Rolf Knobel

A doped semiconductor wafer of float zone-pulled semiconductor material contains a dopant added to a molten material and has a radial macroscopic resistance distribution of less than 12% and striations of &#x2212;10% to +10%. There is also a process for producing a doped semiconductor wafer by float zone pulling of a single crystal and dividing up the single crystal, in which process, during the float zone pulling, a molten material which is produced using an induction coil is doped with a dopant. It is exposed to at least one rotating magnetic field and is solidified. The single crystal which is formed during the solidification of the molten material is rotated. The single crystal and the magnetic field are rotated with opposite directions of rotation and the magnetic field has a frequency of 400 to 700 Hz.

Doped semiconductor wafer of float zone pulled semiconductor material, and process for producing the semiconductor wafer

A silicon single crystal is produced by crucible-free float zone pulling, has a diameter of at least 200 mm over a length of at least 200 mm and is free of dislocations in the region of this length. A silicon wafer is separated from the silicon single crystal by a process for producing the silicon single crystal. The silicon single crystal is produced by crucible-free float zone pulling in a receptacle, in which an atmosphere of inert gas and nitrogen exerts a pressure of 1.5-2.2 bar, the atmosphere being continuously exchanged, with the volume of the receptacle being exchanged at least twice per hour. A flat coil with an external diameter of at least 220 mm is inserted in order to melt a stock ingot. The single crystal is pulled at a rate in a range from 1.4-2.2 mm/min and is periodically rotated through a sequence of rotation angles. The direction of rotation is changed, after each rotation, by a rotation angle belonging to the sequence, a change in the direction of rotating defining a turning point on the circumference of the single crystal, and at least one recurring pattern of turning points is formed, in which the turning points are distributed on straight lines which are oriented parallel to the z-axis and are uniformly spaced apart from one another.

Silicon single crystal produced by crucible-free float zone pulling

A process for producing silicon wafers which have a storage-stable surface and which can be thermally oxidized directly, that is to say, without a prior HF immersion bath, and without the addition of halogen-containing gases, it being possible to achieve an equal or better oxidation result than that achieved by including these measures.

Process for producing storage-stable silicon wafer surfaces having

Silicon wafers are first subjected to an oxidative treatment and subsequey to exposure to organosilicon compounds which contain at least one radical in the molecule which is hydrolyzably bound to the silicon and at least one radical in the molecule having hydrophilic properties. Depending on the compound selected, more or less strongly hydrophilic or hydrophobic properties of the silicon surface can consequently be established under mild conditions. The wafers treated in such a manner have a high storage stability and retain their surface nature even under difficult climatic circumstances. The surface nature present after the oxidative treatment can then be restored particularly easily by hydrolysis.

Process for producing storage-stable surfaces of polished silicon wafers

Growing community of inventors

Burghausen, Germany

Manfred Grundner