Veeco Instruments | Date: 2015-02-10
In a rotating disk reactor for growing epitaxial layers on substrate or other CVD reactor system, gas directed toward the substrates at gas inlets at different radial distances from the axis of rotation of the disk has both substantially the same gas flow rate/velocity and substantially the same gas density at each inlet. The gas directed toward portions of the disk remote from the axis may include a higher concentration of a reactant gas than the gas directed toward portions of the disk close to the axis, so that portions of the substrate surfaces at different distances from the axis receive substantially the same amount of reactant gas per unit area, and a combination of carrier gases with different relative molecular weights at different radial distances from the axis of rotation are employed to substantially make equal the gas density in each region of the reactor. The system may be applied with a combination or carrier gases at multiple gas inlets, a combination of carrier and reactant gases at multiple inlets, and may be used with an arbitrarily large number of gases, when at least two gases of different molecular weights are provided. A linear flow pattern is achieved within the reactor, avoiding laminar recirculation areas, and permitting uniform deposition and growth of epitaxial layers on the substrate.
Veeco Instruments | Date: 2015-08-10
Mass-transfer rate control arrangement and method in which a process precursor mixture is produced containing carrier gas and a process precursor gas. A quantity of the process precursor present in the process precursor mixture is acoustically sensed to produce a sensor output. A dilution gas is provided and the process precursor mixture and the dilution gas are separately conveyed to a diution point, at which a diluted mixture of the dilution gas and the process precursor mixture is achieved. A relative flow rate of the carrier gas and the dilution gas is automatically controlled in response to the sensor output such that the diluted mixture at the dilution point has a prescribed mass transfer rate of the precursor gas.
Veeco Instruments | Date: 2015-03-10
Veeco Instruments | Date: 2015-05-29
An apparatus and method for controlling stray radiation within a CVD chamber. A heater array disposed beneath a wafer carrier for radiatively heating of the wafer carrier includes a peripheral or outermost heating element or elements. Scattered radiation originating from a designated segment of the peripheral heating element(s) can be reduced locally by one of several mechanisms, including reducing the emission (e.g., operating temperature) of the designated segment, or capturing or deflecting a portion of the radiation originating from the designated segment. In one embodiment, an electrical connector on a resistance heating element provides the reduced emission from the designated segment. It has been found that radiation thermometers fixed proximate an axis that extends from the center of the wafer carrier and across the designated segment is subject to less stray radiation, thus providing a more reliable temperature reading in the optical wavelengths.
Veeco Instruments | Date: 2015-02-05
A pressure-adjusting lapping element is included as a structural component of a carrier assembly in a lapping head. The lapping element includes actuator nodes that permit fine tuning of a lapping force applied through the lapping element to a work piece. An actuator assembly is directly attached to the lapping element and manipulates the individual actuator nodes. The lapping element further includes whippletree structure to permit a desired degree of flexibility in the lapping element to respond to force inputs at the actuator nodes.