Read gen930_product_guide.pdf text version

Product Guide

GEN930 MBE System


TODAYS LEADER IN MBE R&D SYSTEMS . . . . . . . . . . . 1 GEN930 SYSTEM DIFFERENCE. . . . . . . . . . . . . . . . 2 GEN930 SYSTEM EQUIPMENT . . . . . . . . . . . . . . . . 3 Growth Chamber . . . . . . . . . . . . . . . . . . . . . . 3 Buffer Chamber . . . . . . . . . . . . . . . . . . . . . . . 4 Load Lock Chamber (optional) . . . . . . . . . . . . . . . . 4 Pumping Ports . . . . . . . . . . . . . . . . . . . . . . . . 4 SUBSTRATE TRANSFER . . . . . . . . . . . . . . . . . . . . 5 Transfer Methodology . . . . . . . . . . . . . . . . . . . . 5 WAFER GROWTH . . . . . . . . . . . . . . . . . . . . . . 6 Substrate Manipulator . . . . . . . . . . . . . . . . . . . . 6 Beam Flux Monitor . . . . . . . . . . . . . . . . . . . . . . 7 In-Situ Monitoring . . . . . . . . . . . . . . . . . . . . . . 7 Source Flange . . . . . . . . . . . . . . . . . . . . . . . . 8 EFFUSION CELLS . . . . . . . . . . . . . . . . . . . . . . 9

Group III Cells .

. . . . . . . . . . . . . . . . . . . . . 9

Group V Cells . . . . . . . . . . . . . . . . . . . . . . . 10 Group II and VI. . . . . . . . . . . . . . . . . . . . . . . 10 Effusion Cell Shutters . . . . . . . . . . . . . . . . . . . . 10 ELECTRONICS/SOFTWARE . . . . . . . . . . . . . . . . . 11 VACUUM SPECIFICATIONS. . . . . . . . . . . . . . . . . 13 MATERIAL SPECIFICATIONS WITH SUMO CELLS . . . . . . 13 WARRANTY STATEMENT . . . . . . . . . . . . . . . . . . 14

GEN930 MBE System Product Guide - 6/03

Page i

Page ii

GEN930 MBE System Product Guide - 6/03


Veeco has long been recognized as the innovator in molecular beam epitaxy (MBE). We hold the most patents for MBE equipment, and changed forever MBE's role in materials research with the development of material-specific effusion cells. Veeco became the world's leading suppler of MBE components with such breakthroughs as valved crackers and SUMO® cells. By applying that MBE know-how to the R&D market, we have recently become today's leading supplier of MBE R&D systems. Even as our silicon-style systems become the new standard in production MBE, we have never lost sight of the critical role materials research plays in shaping future compound semiconductors. That explains our broad line-up of single- and multi-wafer R&D systems. That's the impetus behind our new GEN IIITM - today's most popular low-volume MBE system - and the new GEN930TM system detailed here. In short, no MBE equipment company is more committed to the research community, or offers a more comprehensive R&D system portfolio.

The GEN930 system is the ideal MBE tool for materials research.

GEN930 MBE System Product Guide - 6/03

Page 1


The GEN930 system includes everything you need for your R&D department - whether you're working with III-V, II-VI or more exotic materials. It delivers: · · · · · A modular design that fits your budget, plus it gives you the flexibility to expand the system's capabilities over time. Proven high-quality, high-uniformity epitaxial layers on up to 3" substrates. The world's most proven, reliable and preferred MBE components. The ability to integrate optional analytical equipment for in-situ monitoring of the growth process. The industry's most comprehensive service support.

System Incorporates GEN II Design Elements

The GEN930 system combines the best of our 930 and GEN IITM MBE systems. You get the core technology and up to 16-sample transfer system of our GEN II in a scaleable architecture to meet your application and budget requirements.

The GEN II is the world's standard among single-wafer MBE systems.

The GEN II is the single-wafer standard for R&D MBE with more than 220 installed systems. It holds numerous GaAs and AlGaAs performance records. The GEN930 system now delivers the GEN II system's proven legacy of high performance and its fully qualified, familiar sample transfer system in a simpler, more scaleable design.

Page 2

GEN930 MBE System Product Guide - 6/03


The GEN930 system gives you maximum flexibility in materials research. Its geometry, unique cryopanel, and numerous ports for integrating today's leading edge in situ analytical tools ensure material purity. The reliability of the system has been proven in many of the leading material research laboratories around the world. The main components of the GEN930 system are: · · · · · · · · · · UHV Growth Chamber Buffer Chamber (with optional outgassing stage) Load Lock Chamber (optional) Pumping System(s) GEN II Wafer Transport System Source Flange Substrate Manipulator Effusion Cells/Shutters Electronics Software

Growth Chamber

The GEN930 system's growth chamber accommodates substrates up to 3" in diameter. It features a main LN2 cryopanel plus an exclusive radial vane LN2 cryopanel based on the GEN II system that thermally and optically isolates each heated source. The latter prevents radiation from affecting temperature settings in adjacent sources. The cryopanel design also minimizes the risk of material cross-contamination - critical in research on III-V, II-VI, oxides and other exotic materials requiring the utmost in material purity. The growth chamber's 25º tilted vertical geometry maximizes the source loading capacity. Combined with the radial vane cryopanel design, it also eliminates the risk of material flakes entering the effusion cell orifice. The chamber's source flange has nine effusion cell ports and shutters, plus two auxiliary ports on the bottom of the growth chamber for installing effusion cells with integral shutters. The total of 11 source ports allows the utmost in material source selection flexibility.

The GEN930 system's cryopanels minimize material cross contamination.

GEN930 MBE System Product Guide - 6/03

Page 3

Buffer Chamber

The buffer chamber is standard for the multi-sample, two-chamber GEN930 system, and isolates the growth chamber from atmosphere for sample loading. This module, which is the same one used on the GEN II system, can hold up to 16 samples at a time. It includes a vacuum chamber, manual gate valve, magnetically coupled manual transfer assembly, ion gauge, four transfer viewports, transfer rod and rails, and blank ports for pumps. An optional substrate outgassing stage capable of temperatures up to 600º is available, as is a second trolley for storage of up to 16 additional substrates.

The system's wafer introduction outgas feature helps remove impurities from substrates prior to growth.

Load Lock Chamber (optional)

The GEN930 system offers an optional load lock chamber that permits quick pump down, and delivers a 200ºC internal bakeout for outgassing water vapor from substrates and holders. This optional chamber is isolated via a manual gate valve and a dedicated turbomolecular pumping system. Using it allows for 200ºC internal bakeout prior to introduction into the buffer chamber. The load lock chamber may be added to the system at any time to enable a three-chamber configuration.

Pumping Ports

Three pumps can be mounted directly into the growth chamber to maximize conductance. All types of UHV pumps are possible, such as a 400 lit./sec. ion pump with integral Ti sublimation pump, a 2,200 lit./sec. turbomolecular pump, a 1,500 or 3,000 lit./sec. cryopump, or a Ti sublimator with LN2 shroud. The three pumping ports ensure flexibility in delivering a pure growth environment tailored for any application.

Phosphorus Recovery

The GEN930 system features a phosphorus recovery system to safely capture and dispose of much of the phosphide waste generated in the growth chamber. Equipment includes an isolated pumping station that attaches directly to the growth chamber, and can be removed when not in use. A section of this station contains a UHV liquid nitrogen-cooled trap to capture phosphorus before it migrates to the pumps. Once the phosphorus is condensed onto the cold trap, a mix of oxygen and nitrogen can be bled into the volume to create stable oxides of phosphorus. The trap can be easily removed for cleaning and material disposal.

Page 4

GEN930 MBE System Product Guide - 6/03


The GEN930 system's transfer mechanism - the same as that in the GEN II, ensures reliability and ease of use - all within an ultra-high vacuum (UHV). Users can even make transfer mechanism adjustments without venting the buffer or optional load lock chambers. Substrates are mounted onto molybdenum holders and loaded up to 16 at a time onto the I-beam trolley. The trolley holds the substrates vertically to prevent contamination by particulates. Magnetic coupling moves the trolley through the buffer chamber or optional load lock chamber while eliminating the need for a bellows to translate linear or rotational motion while under vacuum. The trolley and substrates can be heated to 200ºC via quartz halogen heaters in the optional load lock chamber to remove water vapor before transfer into the buffer chamber. An optional outgassing stage is available in the buffer chamber for thermal cleaning of individual substrates up to 600ºC.

The GEN930 system's transfer mechanism is the same as that of the GEN II system.

Transfer Methodology

A magnetically coupled transfer rod moves the substrates into the growth chamber and onto the substrate manipulator in the following steps: 1. The transfer gate valve is opened. The magnetically coupled trolley moves the substrate holder into position in front of the manipulator. 2. The manipulator's bayonet device is extended forward. The bayonet's three points insert into the three slots in the substrate holder. The bayonet device is rotated slightly to lock the holder in place. 3. The transfer rod is retracted, leaving the substrate holder on the bayonet device. 4. The bayonet device is retracted, pulling the substrate holder into the "oven" formed by the substrate heater and surrounding heat shielding for growth.

GEN930 MBE System Product Guide - 6/03

Page 5


The GEN930 ensures high-quality and high-uniformity growth through its integrated growth chamber design elements, its proven effusion cell sources, and its comprehensive in situ monitoring options.

Substrate Manipulator

The GEN930 system incorporates the GEN II system's substrate manipulator design. The growth stage handles substrates up to 3" in diameter. Bayonet pins lock into sample carrier ring slots to hold the specimen in front of the heat element. The continuous azimuthal rotation (CAR) assembly can continuously rotate the substrate during growth to improve both substrate thermal and film growth uniformities. The heavy-duty construction and shielded electrical cables ensure trouble-free operation.

Substrate Manipulator


The manipulator has two degrees of rotation built into its design: sample axis continuous rotation (azimuthal) and stage head positional rotation. The manipulator stage has primary functional positions for growth and substrate transfer (intermediate positions are possible for special processing or characterization requirements). The transfer position is also used to locate the built-in beam flux monitor (BFM) at the sample's epitaxial growth position for measurement of beam flux partial pressures. This positioning eliminates the frequent and inconsistent calibration calculations required with other systems.

Wafer on CAR at 900°C

Continuous variable speed (0-120 RPM) rotation of the sample during growth ensures uniform heating and coating of the epitaxial film across the substrate surface. Temperature stability is ±1ºC non-rotating and ±4ºC rotating at 5 RPM from 200ºC to 750ºC as measured by the substrate holder thermocouple. Temperature uniformity of central 2.75" of 3" diameter GaAs substrate at 550ºC is ±5ºC as measured by an infrared pyrometer. A rotational indexing function is also used to align the appropriate substrate crystal orientation for performing RHEED analysis. An optional manipulator upgrade can accommodate optical access to the substrate backside for advanced temperature measurements, such as band-edge spectroscopy or wafer backside pyrometry.

Page 6

GEN930 MBE System Product Guide - 6/03

Beam Flux Monitor

The beam flux monitor (BFM) measures and calibrates the beam equivalent pressure (BEP) produced by an effusion cell. The BFM in the GEN930 system is a shielded ion gauge mounted as an integral part of the manipulator head, 180º opposite the sample. The gauge is rotated into the sample's epitaxial growth position to measure the pressure of the arriving source molecular beam. Since a high degree of temperature stability and flux control is inherent in the cells, a source can be calibrated with the BFM to quantify a flux value for a given source's operating parameters. Once the sources are calibrated, the substrate can be rotated into the growth position where the calibrated fluxes are used to build the epitaxial layers of the total film structure.

In-Situ Monitoring

One of the distinguishing features of the GEN930 system is the large number of optical access ports, which can accommodate numerous in-situ monitoring techniques critical to materials research. The growth chamber can incorporate such in-situ monitoring techniques as: · Reflected high energy electron diffraction (RHEED)--positioned so RHEED studies can be performed while the substrate is in the normal growth position Ellipsometry--73º angle ports are standard; others are available upon request Optical flux monitoring Ion gauge beam flux monitoring Pyrometry (Emissivity corrected models available) Reflectance spectroscopy RGA (Residual Gas Analyzer) Band edge spectroscopy Quartz crystal monitor Others available upon request

· · · · · · · · ·

GEN930 MBE System Product Guide - 6/03

Page 7

Source Flange

The growth chamber source flange includes 9 effusion cell ports symmetrically arranged around a central pyrometer port, plus two auxiliary ports at larger incident angles that are ideal for dopant materials. This configuration provides maximum flexibility when planning the arrangement of materials within the source flange in addition to maximizing potential growth campaign length. Six of the ports have deep angles to maximize holding capacity of the molten source materials. Thermal isolation of each effusion cell is provided by the radial vane LN2 cryopanel. LN2 (or water, water-glycol mixture) surrounds the hot zones of each of the effusion cells. Physical isolation is accomplished by maximizing the distance between cells, and by the LN2 panel. The latter serves as an "isolation fence" to prevent material cross-talk. Effusion cells can be swapped out for other UHV components such as a compact e-beam or ion source, plasma source or even analytical instrumentation.

Page 8

GEN930 MBE System Product Guide - 6/03


Veeco is the world's leading supplier of effusion cells for MBE. The GEN930 system benefits from full compatibility and integration of the company's extensive line of sources--the same effusion cells used/qualified on our GEN II and GEN III systems.

A sample effusion cell selection may consist of:

· · · · · · One 500cc valved cracker for arsenic with automated valve positioner Two SUMO cells for gallium and indium One 400g SUMO cell for aluminum Two 5cc dopant effusion cells for silicon and beryllium UNI-BulbTM RF plasma source for nitrogen Other effusion cell choices include proven solutions for antimony, phosphorus and other materials.

Group III Cells

Veeco's patented SUMO cells are excellent for group III elements. The SUMO cell for gallium and indium features a heat-shielding cap. Coupled with the cell's optimized dual filament design, it allows the cell to be run with 100% of the power to the tip filament while the total power used is less than a conventional cell. The SUMO cell's novel crucible design provides all of the advantages of a crucible with a low flux transient insert, plus it reduces defect densities and provides a large useful capacity. The PBN crucible's small aperture provides excellent flux uniformity. The SUMO cell for aluminum features a unique enclosure to heat sink the cell's tip. This helps provide excellent flux uniformity. The optimized dual filament design and cell enclosure allows the cell to run with 100% of the power to the primary while maintaining a large thermal gradient to the lip of the crucible. This minimizes the tendency of aluminum to creep from the crucible.

GEN930 MBE System Product Guide - 6/03

Page 9

The benefits of SUMO cells include: · · · · · ·

Thickness uniformity across a 3" wafer represented as a mapping of quantum well photoluminescense. The MQW structure was grown using a SUMO Ga cell in a MOD GEN II system. Uniformity better than ±1% was achieved.

Hot-lip dual filament design minimized defects (Ga and In) Cold-lip filament design minimizes creep (Al) Lower background impurities Excellent flux uniformity Increased capacity Undetectable flux transients Minimized depletion effect Lower thermal load

· ·

Group V Cells

Group V materials can be used in any of the source flange positions in any of these three sources: The valved cracking effusion cell includes a unique valve mechanism to control the amount of evaporant entering the growth chamber. This eliminates the need for thermal adjustments. The beam can be initiated, terminated or modulated by varying the valve position. Field proven models are available for arsenic, phosphorus and antimony. Both the standard crackers (non-valved) and the low-temperature effusion cells are available for arsenic and antimony.

Group II and VI

Many II-VI materials have high vapor pressures. The Veeco valved crackers are available for Se, Te, CdTe, Cd and S, and represent today's leading components for II-VI material introduction. Also available is a patented, low-temperature cell that provides better reproducibility and stability for these materials than standard effusion cells.

Effusion Cell Shutters

An equal number of soft-action, pneumatic linear motion shutters are individually mounted on a 4.5"/114mm CF flange for easy removal and cleaning with blade materials matched to each effusion cell. Shutters are designed for 1 million cycles, and times to open and close are user-configurable between 100-300mns. The opening and closing motions are dampened to minimize shock and vibration. This alleviates material flaking from shutter actuation. Each shutter actuator is fully shielded to prevent condensed material from reaching moving shutter parts.

GEN930 MBE System Product Guide - 6/03

The system's shutters are designed for 1 million cycles.

Page 10


Veeco is the only company providing electronics designed exclusively for MBE. The GEN930 system benefits as a result. The DC power module is CE-certified and capable of driving the filament loads associated with any of the effusion cells or substrate heaters. It combines a proportional/integral/derivative (PID) temperature controller with an internally regulated power matching DC power supply using advanced control algorithms to provide a high degree of stability and temperature reproducibility. It is designed with circuitry that supports RS-232 or RS-422/85 digital control interface for remote operation and data acquisition. Its compact size optimizes electrical rack space usage. The system's sophisticated CE-certified motion controller is used for all MBE system motion applications. Brushless DC servo motors are used in all motion control applications. Motors are configured with optical encoders, enabling angular position resolution within ±0.1º. Torque monitoring functions are incorporated to detect fault conditions and changes in the mechanism operating parameters, which can signal the need for preventative maintenance.

DC Power Module

Other Control Equipment

· Hand-held versions of the effusion cell shutter and RHEED gun controller provide the system operator with remote control capabilities Granville-Phillips gauge controller for each ion gauge Rotation controller for substrate manipulator Pump controllers and power supplies as needed

· · ·

GEN930 MBE System Product Guide - 6/03

Page 11


The GEN930 system features MollyTM, a robust software platform that enables the MBE operator to develop and use layer structure recipes. The software, proven on more than 100 MBE R&D systems, provides high-level constructs that automate growth by working from a recipe file that describes the desired epitaxial layer structure. The operator doesn't need to describe details of the process sequence. Molly software provides fully automated control of: ·

Molly Software automates process control.

Setpoint temperatures and ramp rates with manual override Shutter operation with manual override Substrate rotation and position Pneumatic gate valve positioning Effusion cell calibration Flux monitoring

· · · · ·

It also acquires data from vacuum gauges, pyrometers, PID controllers, shutter and valve actuators, RGA, RHEED, and any other signal-generating instrument with suitably equipped analog output interfaces.

Molly's `Editors' Control Growth

Molly's user-friendly interface delivers £ msec average performance and allows multi-tasking. There are no preset limits on the number of independent processes it can run. Two main functions drive operation:

Configuration Editor. Adapts Molly to the system. It defines how the

system is configured and what equipment is current being used. It updates the program when changes are made, such as when adding a new effusion cell.

Recipe Editor. Creates the structure growth blueprint. Recipes are composed of layers. Recipe Editor can designate recipes in terms of shutter open times and source material temperature as well as in terms of layer thicknesses and layer composition.

Molly's object-oriented structuring lets the operator describe the samples to be grown by their composition, plus it eliminates excessive manual entry of commands such as shutter position and cell temperature.

Page 12

GEN930 MBE System Product Guide - 6/03

The Windows®-based user interface is very intuitive. It makes the overview screen very configurable. Molly's program language interfaces growth control with user-defined diagnostic or analytic techniques. It can expand easily to adapt to new developments in growth control technology.


All materials in the GEN930 system are UHV compatible, low vapor pressure materials, such as 304 stainless steel, tantalum, tungsten, aluminum, and pyrolytic boron nitride (PBN). Demountable ports are sealed using ConFlat or Wheeler flanges with all-metal gaskets except the load-lock entry door, which uses a high-quality Viton seal for quick access between bakeouts (copper gasket required during bakeout). The system is bakeable to 200ºC.

Chamber Growth Buffer Load Lock Standard Pump 400 lit/sec Ion/Ti sublimation pump, with 1500 lit/sec cryopump, and Viton-sealed gate valves 160 lit/sec ion pump with manual gate valve 250 lit/sec turbomolecular pump Base Pressure <5x10-11 Torr <5x10-10 Torr <5x10-8 Torr


A. Thickness uniformity of GaAs (excluding outer 2-3 mm of wafer) - < ±1.0% for a 2-in wafer at a growth rate of 1mm/hr - < ±1.5% for a 3-in wafer at a growth rate of 1mm/hr B. Dopant uniformity in GaAs (excluding outer 2-3 mm of the wafer) - < ±1.0% for a 2-in wafer at a growth rate of 1mm/hr - < ±1.5% for a 3-in wafer at a growth rate of 1mm/hr C. Composition uniformity for the Al-content in AlGaAs (~30%Al) (excluding the outer 2-3 mm of the wafer) of - < ±1.0% for a 2-in wafer at a growth rate of 1mm/hr - < ±1.5% for a 3-in wafer at a growth rate of 1mm/hr D. Surface defect density: <100 cm-2

GEN930 MBE System Product Guide - 6/03

Page 13


The complete text of Veeco's warranty policy is stated in its "Veeco Terms and Conditions of Sales." For a copy, contact the Veeco Sales Department. All Veeco manufactured MBE systems, effusion cells, and related electronic items are warranted against defects in material and workmanship for one year, provided they are used consistently in UHV environments, and aren't damaged by crucible failure, material overflow or excessive power input. Electronic equipment not manufactured by Veeco Applied Epi is covered by the original manufacturer's warranty.

Page 14

GEN930 MBE System Product Guide - 6/03

Veeco is the world's leading supplier of molecular beam epitaxy (MBE) equipment. Our MBE effusions cells, R&D systems and cluster tool production systems are today's standards. Veeco is committed to further advancing MBE technology to support next generation wireless and optoelectronic devices. To that end, we have launched a new Process Integration Center (PIC). This state-of-the-art facility lets Veeco provide process and tool solutions to its customers up front in the development process. The PIC also features an expanded MBE source development department that facilitates collaboration with customers seeking to test new material sets and develop advanced devices. In addition, we offer Veeco's broad suite of complementary metrology and process equipment products. Whatever enabling technology you need-MBE, IBD, IBE, PVD, AFM or SPM-we have them. Plus all our products and processes are backed by the industry's most comprehensive global service network. Our goal is to make your MBE operation thrive. Whether you seek a collaborative partner on device development, the world's premiere MBE tools, or a company with the best solutions for your nanoscale world, we are your company. Please contact us with any questions.

CORPORATE HEADQUARTERS Veeco Instruments Inc. 100 Sunny side Boulevard Woodbury, NY 11797 TEL (516) 677-0200 FAX (516) 714-1200 EUROPE Veeco Instruments S.N.C. 11, Rue Marie Poussepin Zi De La Gaudree 91412 Dourdan, France TEL (33) 164 59 35 20 FAX (33) 164 59 72 22 JAPAN Nihon Veeco KK 6-26 Sanbancho Chiyoda-ku Tokyo, Japan 102-0075 TEL (81) 3-3262-6151 FAX (81) 3-3262-6155 ASIA/PACIFIC Veeco Asia :te. Ltd. 10 Yoh Guan Road #03-03 TT International Tradepart Singapore 608838 TEL (65) 6794-7941 FAX (65)6794-7942

Solutions for a nanoscale world.

MBE OPERATIONS 4900 Constellation Drive St. Paul, MN 55127 USA TEL 651-482-0800 FAX 651-482-0600 WEB EMAIL [email protected]

© 2003 Veeco Instruments Inc. All rights reserved. GEN930, GEN II, GEN III, UNI-Bulb, and Molly are trademarks, and SUMO is a registered trademark of Veeco.


18 pages

Find more like this

Report File (DMCA)

Our content is added by our users. We aim to remove reported files within 1 working day. Please use this link to notify us:

Report this file as copyright or inappropriate