Memc Electronic Materials, Inc.

Monsanto Company

Corner Star Limited

Sunedison Semiconductor Limited

Harold W Korb

Robert J Falster

Steven Lawrence Kimbel

Joseph C Holzer

Richard Joseph Phillips

Hariprasad Sreedharamurthy

Richard G Schrenker

Lu Fei

John D Holder

Milind S Kulkarni

Kyong-Min Kim

Dick S Williams

Martin Jeffrey Binns

Luciano Mule'Stagno

Shailendra B Rathod

Cynthia F Hall

Carissima Marie Hudson

Mohsen Banan

Stephan Haringer

Salvador Zepeda

Carl F Cherko

Marco Zardoni

Sadasivam Chandrasekhar

Larry E Drafall

Christopher Vaughn Luers

Roger W Shaw

Luciano Mule&prime;Stagno

Verlin A Lauher

Steven M Joslin

Klaus Drescher

Claudia P Reed

Systems and methods for forming an ingot from a melt are disclosed. A system includes a crucible defining a cavity for receiving the melt, and a first and second barrier to inhibit movement of the melt. A first passageway and a second passageway are arranged to allow the melt located within an outer zone to move into and through a transition zone and into an inner zone. Conditioning members are placed in at least one of the zones and arranged to contact the melt to reduce the number of micro-voids in the melt.

System for forming an ingot including crucible and conditioning members

Methods for producing crucibles for holding molten material that contain a reduced amount of gas pockets are disclosed. The methods may involve use of molten silica that may be outgassed prior to or during formation of the crucible. Crucibles produced from such methods and ingots and wafers that are produced from crucibles with a reduced amount of gas pockets are also disclosed.

Methods for producing crucibles with a reduced amount of bubbles

Pulling systems are disclosed for measuring the weight of an object coupled to a first end of a cable. The cable is routed over a pulley suspended from a load cell. The force exerted by the cable on the pulley is used to calculate the weight of the object. The second end of the cable is coupled to a drum which when rotated pulls the object by wrapping the cable around the drum. An arm is coupled to the pulley at one end and to a frame at another end. A path travelled by the cable between the pulley and the drum is substantially parallel to a longitudinal axis of the arm. Horizontal force components are transmitted by the arm to the frame and do not affect a force component measured by the load cell, thus increasing the accuracy of the calculated weight of the object.

Systems for weighing a pulled object

Controlling crystal growth in a crystal growing system is described. The crystal growing system includes a heated crucible including a semiconductor melt from which a monocrystalline ingot is grown according to a Czochralski and the ingot is grown on a seed crystal pulled from the melt. The method includes applying a cusped magnetic field to the melt by supplying an upper coil with a first direct current (I) and supplying a lower coil with a second direct current (I). The method also includes supplying the upper coil with a first alternating current (I) and supplying the lower coil with a second alternating current (I) to generate a time-varying magnetic field, wherein the time-varying magnetic field generates a pumping force in the semiconductor melt.

Generating a pumping force in a silicon melt by applying a time-varying magnetic field

A system for growing silicon crystals that facilitates controlling a shape of a melt-solid interface is described. The crystal growing system includes a heated crucible including a semiconductor melt from which a monocrystalline ingot is grown according to a Czochralski process. The ingot is grown on a seed crystal pulled from the melt. The method includes applying an unbalanced cusped magnetic field to the melt, and rotating the ingot and the crucible in the same direction while the ingot is being pulled from the melt.

Controlling a melt-solid interface shape of a growing silicon crystal using an unbalanced magnetic field and iso-rotation

A system for measuring the weight of an object while pulling the object upward includes a puller having a frame and a cable having a first end coupled to the object and a second end engaging a second cylinder. At least a portion of the cable engages the outer circumferential surface of a first cylinder and the second cylinder. The apparatus also includes an upper arm and an actuator. A force measurement device is coupled to the first cylinder and to the upper arm and measures the weight of the object. The actuator is operable to lower and raise the weight measurement device and the first cylinder. In some embodiments, the position of the cable with respect to the frame may be adjusted by a dampening system or a bushing.

Systems for weighing a pulled object having a changing weight

A method and system for use in combination with a crystal growing apparatus for growing a monocrystalline ingot according to a Czochralski process. The crystal growing apparatus has a heated crucible including a semiconductor melt from which the ingot is pulled. The ingot is grown on a seed crystal pulled from the melt. A time varying external magnetic field is imposed on the melt during pulling of the ingot. The magnetic field is selectively adjusted to produce pumping forces in the melt to control a melt flow velocity while the ingot is being pulled from the melt.

Electromagnetic pumping of liquid silicon in a crystal growing process

Epitaxial wafers comprising a single crystal silicon substrate comprising agglomerated vacancy defects and having an axially symmetric region in which silicon self-interstitials are the predominant intrinsic point defect and which is substantially free of agglomerated defects, and an epitaxial layer which is deposited upon a surface of the substrate and which is substantially free of grown-in defects caused by the presence of agglomerated intrinsic point defects on the substrate surface upon which the epitaxial layer is deposited.

Single crystal silicon wafer having an epitaxial layer substantially free from grown-in defects

A process for producing silicon which is substantially free of agglomerated intrinsic point defects in an ingot having a vacancy dominated region. An ingot is grown generally in accordance with the Czochralski method. While intrinsic point defects diffuse from or are annihilated within the ingot, at least a portion of the ingot is maintained above a temperature Tat which intrinsic point defects agglomerate. The achievement of defect free silicon is thus substantially decoupled from process parameters, such as pull rate, and system parameters, such as axial temperature gradient in the ingot.

Process for cooling a silicon ingot having a vacancy dominated region to produce defect free silicon

A process for heat-treating a single crystal silicon wafer to dissolve agglomerated vacancy defects and to influence the precipitation behavior of oxygen in the wafer in a subsequent thermal processing step. The process includes subjecting the wafer to a heat treatment to dissolve agglomerated vacancy defects, rapid thermally annealing the heat-treated wafer to cause the formation of crystal lattice vacancies throughout the wafer and controlling the cooling rate of the annealed wafer to allow some, but not all, of the crystal lattice vacancies to diffuse to the front surface to produce a wafer having a nonuniform vacancy concentration with the concentration of vacancies in the bulk of the wafer being greater than the concentration in the surface layer.

Process for producing thermally annealed wafers having improved internal gettering

The present invention is directed to an epitaxial wafer comprising a single crystal silicon substrate having an axially symmetric region in which silicon self-interstitials are the predominant intrinsic point defect and which is substantially free of agglomerated defects, and an epitaxial layer which is deposited upon a surface of the substrate and which is substantially free of grown-in defects caused by the presence of agglomerated silicon self-interstitial defects on the substrate surface upon which the epitaxial layer is deposited.

Epitaxial wafer substantially free of grown-in defects

A process for growing single crystal silicon ingots of which portions are substantially free of agglomerated intrinsic point defects. An ingot is grown generally in accordance with the Czochralski method. A first portion of the ingot cools to a temperature which is less than a temperature T at which agglomeration of intrinsic point defects in the ingot occurs during the time the ingot is being grown, while a second portion remains at a temperature above T . The second portion of the ingot is subsequently maintained at a temperature above T to produce a portion which is substantially free of agglomerated intrinsic point defects.

Process for growing defect-free silicon wherein the grown silicon is cooled in a separate chamber

A process for heat-treating a single crystal silicon wafer to dissolve agglomerated vacancy defects and to influence the precipitation behavior of oxygen in the wafer in a subsequent thermal processing step is disclosed. The wafer has a front surface, a back surface, and a central plane between the front and back surfaces. In the process, the wafer is subjected to a thermal anneal to dissolve agglomerated vacancy defects present in a stratum extending from the front surface toward the center of the wafer. The annealed wafer is then heat-treated to form crystal lattice vacancies, the vacancies being formed in the bulk of the silicon. The heat-treated wafer is cooled from the temperature of said heat treatment at a rate which allows some, but not all, of the crystal lattice vacancies to diffuse to the front surface to produce a wafer having a vacancy concentration profile in which the peak density is at or near the central plane with the concentration generally decreasing in the direction of the front surface of the wafer.

Thermally annealed wafers having improved internal gettering

A process for growing single crystal silicon ingots which are substantially free of agglomerated intrinsic point defects. An ingot is grown generally in accordance with the Czochralski method. No portion of the ingot cools to a temperature which is less than a temperature T,at which agglomeration of intrinsic point defects in the ingot occurs during the time the ingot is being grown. The achievement of defect free ingots is thus substantially decoupled from process parameters, such as pull rate, and system parameters, such as axial temperature gradient in the ingot.

Growing community of inventors

Chesterfield, MO, United States of America

Harold W Korb