Abstract:
A doped silicon single crystal having a resistivity variation along a longitudinal and/or radial axis of less than 10% and a method of preparing one or a sequential series of doped silicon crystals is disclosed. The method includes providing a melt material comprising silicon into a continuous Czochralski crystal growth apparatus, delivering a dopant, such as gallium, indium, or aluminum, to the melt material, providing a seed crystal into the melt material when the melt material is in molten form, and growing a doped silicon single crystal by withdrawing the seed crystal from the melt material. Additional melt material is provided to the apparatus during the growing step. A doping model for calculating the amount of dopant to be delivered into the melt material during one or more doping events, methods for delivering the dopant, and vessels and containers used to deliver the dopant are also disclosed.
Abstract:
A doped silicon single crystal having a resistivity variation along a longitudinal and/or radial axis of less than 10% and a method of preparing one or a sequential series of doped silicon crystals is disclosed. The method includes providing a melt material comprising silicon into a continuous Czochralski crystal growth apparatus, delivering a dopant, such as gallium, indium, or aluminum, to the melt material, providing a seed crystal into the melt material when the melt material is in molten form, and growing a doped silicon single crystal by withdrawing the seed crystal from the melt material. Additional melt material is provided to the apparatus during the growing step. A doping model for calculating the amount of dopant to be delivered into the melt material during one or more doping events, methods for delivering the dopant, and vessels and containers used to deliver the dopant are also disclosed.
Abstract:
A pendulum gate valve (10) including an expandable gate (12) which pivots when unexpanded to selectively block a vacuum or other pressure-differential passage (20). The valve includes a valve plate (56) sealing one side of the passage and a ring (88) or barrier plate (154) abutting an opposed side of the passage when the gate member is expanded. A compression spring (106) biases apart the valve plate and ring to close the valve by means of respective two-stage hangers attached thereto, extending along the spring, and having distal ends capturing the spring. Pneumatic pressure (116) applied to a pneumatic cavity (114) formed between the middles of the two-stage hangers (66, 102) and accommodating the spring forces apart the valve plate and ring to open the valve in the blocking position. Thereby if pressure fails, the valve fails to a sealed state. The axially movable valve or barrier plate is advantageously water cooled (60) to allow use with a heated processing chamber.