SILTRONIC AG

Disclosed is a process for manufacturing semiconductor wafers containing a gas-phase epitaxial layer in a deposition chamber, involving removing, from the deposition chamber by etching the deposition chamber, material settled in the deposition chamber during preceding coating processes; performing successive coating operations in the etched deposition chamber, each of said coating operations involving having a robot place a substrate wafer on a susceptor having a circular circumference, the robot moving the substrate wafer into a drop-off position and placing it on the susceptor, the center of the substrate wafer not lying over the center of the susceptor in the drop-off position because of a predefined corrective parameter; and depositing an epitaxial layer on the substrate wafer such that a semiconductor wafer containing an epitaxial layer is produced, characterized in that for each first substrate wafer moved by the robot into the drop-off position, the value of the predefined corrective parameter corresponds to a mean value of differences in the positions of a number of previously coated substrate wafers which had been the first substrate wavers to be coated following a preceding chamber etching operation.

A β-Ga 2 O 3 layer is grown on a substrate by: performing a first deposition cycle at a first growth rate using oxygen and a precursor including Ga, the first deposition cycle having a thickness of at least 3 atomic layers of β-Ga 2 O 3 and at most 20 atomic layers of β-Ga 2 O 3 ; determining a regression curve for a layer surface reflectivity using tuples of a measured first layer surface reflectivity and having a first layer thickness; and performing a second deposition cycle including measuring a second layer thickness and a second layer surface reflectivity, with a predetermined second growth rate determined from the first growth rate multiplied by a correction factor, having a defined lower and upper limit.

A device is for drying disc-shaped substrates. The device has an elongated body, which tapers upwards to form a wedge having an angle α between two surfaces and an upper edge. The upper edge is suitable for holding the disc-shaped substrates. The two surfaces have more than one hole, each forming channels, which extend to a lower drainage part of the elongated body.

A side of a semiconductor wafer is cleaned in the following order: (1) executing a first cleaning step, cleaning with ozonized water, and a subsequent rinsing step, rinsing with purified water; (2) executing a second cleaning step, which includes, executing a first treatment step, including treating with ozonized water, which is followed by executing a second treatment step, treating with a hydrogen fluoride (HF)-containing liquid, where the second cleaning step may be repeated multiply; (3) executing a third cleaning step, cleaning with ozonized water, and executing a subsequent rinsing step, rinsing with purified water; and (4) executing a drying step. A preliminary cleaning step, which includes cleaning the side of the semiconductor with water, is executed directly before the first cleaning step so that the side of the semiconductor wafer is still wet while the first cleaning step commences.

A method produces a single crystal of silicon by pulling the single crystal from a melt. The melt is in a crucible and includes phosphorus and boron as dopants in a ratio of not more than 0.41. The boron is in the melt with a concentration of 5.0×10 14 to 2.2×10 15 atoms/cm 3 . The single crystal has a cylindrical section having a diameter of at least 300 mm, which is surrounded by a heat shield while pulled from the melt. A lower edge of the heat shield is further than 18 mm from a melt surface. The single crystal is pulled at 8-13 rpm. A horizontal magnetic field is also applied to the melt, with a magnetic flux density of the horizontal magnetic of 2000-3000 Gs.

A device is for drying disc-shaped substrates. The device has an elongated body, which tapers upwards to form a wedge having an angle α between two upper surfaces and an upper edge. The upper edge is configured to support a disc-shaped substrate. An upper surface of the two upper surfaces has a groove having an increasing groove depth with increasing distance from the upper edge.

Unknown particles on a surface of a semiconductor wafer are classified by applying a range of particles of known chemical composition and different sizes onto a test wafer, measuring the sizes of a plurality of the particles and spectrally analyzing a makeup of the particles by energy-dispersive x-ray spectroscopy, followed by ascertaining a substantive content therefrom; creating a best-fit curve to the size and substantive content of the particles; measuring the particle size of an unknown particle and recording its spectrum by energy-dispersive x-ray spectroscopy and classifying the unknown particle as the result of a comparison of the size and the substantive content of the unknown particle with the best-fit curve.

A process produces a single silicon crystal doped with n-type dopant by pulling the single crystal, surrounded by a heat shield, in a reactor chamber, by the CZ method, from a melt. A solid dopant is heated in a dopant crucible of a sublimating unit outside the reactor chamber to a temperature at which a gaseous dopant is formed. The gaseous dopant is supplied through a conduit to a surface of the melt, including by: bringing a control valve, which is between the sublimating unit and the reactor chamber, into a mandated open state as soon as a pressure difference between the pressure in the sublimating unit and the pressure in the reactor chamber has grown to a predetermined value; and controlling the open state of the control valve with a setpoint pressure in the sublimating unit as command variable and the pressure difference as controlled variable of the control.

Wafers are sliced from a workpiece using a wire saw during slicing operations. The wire saw has a wire web of sawing wire and a setting device. The wire web is stretched in a plane between wire guide rollers that are mounted between fixed and moveable bearings. During each of the slicing operations, the setting device feeds the workpiece through the wire web along a feed direction perpendicular to a workpiece axis and perpendicular to the plane of the wire web. During each of the slicing operations, the movable bearings move oscillatingly axialy. The feeding of the workpiece through the wire web includes a simultaneous displacement of the workpiece along the workpiece axis using the setting element in accordance with a correction profile, which includes an oscillating component that is opposite to the effect which the axial moving of the movable bearings has on the shape of the sliced-off wafers.

An apparatus produces a doped Czochralski crystal. The apparatus includes: a pressure vessel; a crucible in the pressure vessel for containing liquid silicon; and a second apparatus for doping the melt. The second apparatus includes: a housing; a reservoir vessel holding a dopant; a conveyor belt conveying the dopant; a third apparatus for shaping a dumped bed on the conveyor belt; and a pipe whose first end is accessible by the dopant from the conveyor belt and whose second end points in a direction of the liquid silicon and is closed off from the liquid silicon. The third apparatus has a half-pipe having a diameter smaller than a width of the conveyor belt, which is closed on one side, the other side being open, and is arranged over the conveyor belt such that the open side points in the direction of conveyance of the dopant.