With the superior flux control of the Corrosive Series Valved Cracker, complex structures not possible with conventional thermally controlled sources can be achieved. Mixed Group V layers of varying compositions can be grown without the frequent recalibration procedures necessary when using standard sources. SIMS analysis of a continuously graded GaAs1-xSbx layer demonstrates the excellent flux control available when using two Group V valved crackers, with identical results achieved at two different growth rates.

• Patented all-PBN crucible and valve mechanism with more than 175 in the field
• Only valved antimony source with proven results
• Utilizes a nozzle for excellent flux uniformity and reduced material waste
• Highly reproducible mechanical flux control
• Large charge capacity
• Permits operation in cracked or uncracked mode
• Compatible with Sb, Te, Cd, CdTe, Zn and Mg

The patented 91制片厂Corrosive Series Valved Cracker is the only proven all-PBN valved source available on the market today. This innovative technology offers valved flux control for reactive high-vapor pressure materials (such as antimony and tellurium) not compatible with the metal crucibles and valves of traditional valved sources. The source design utilizes an entire valve assembly, crucible and conductance tube constructed exclusively of pyrolytic boron nitride (PBN) to protect them from corrosion.

The valve assembly is removable, allowing easy loading of the large capacity crucible through the conductance tube. The crucible is heated to generate a beam flux. Gas flow is regulated through the PBN valve, providing rapid flux stabilization, quick shut-off and excellent reproducibility. In the cracking zone, a molecular flux may be thermally cracked to smaller molecular or atomic species. The source can also be operated in uncracked mode, if desired.

With recent enhancements, the Mark V Corrosive Series Valved Cracker incorporates a nozzle that provides excellent flux uniformity and reduced material waste. This improvement in material utilization results in:

• Material cost savings
• Longer campaigns
• Shorter system cleaning time
• Less hazardous waste generation
• Reduced memory effects
• Lower particulate levels and flaking
• Reduced system window coating

The patented Valved Cracker for Phosphorus is uniquely tailored to provide a controlled and reproducible P2 flux from a solid phosphorus charge. The multi-zone crucible is designed for in situ conversion from commercially available red phosphorus to the more reactive white phosphorus with its advantageous evaporation characteristics.

• Patented design with more than 175 in the field
• Compatible with high-temperature outgassing
• A proven effective solid source alternative to phosphine (PH3)
• Vacuum sealed crucible to optimize material quality

Veeco鈥檚 unique thermal control system features independent heaters for the red and white phosphorus zones, and an air cooling jacket on the white phosphorus reservoir. Both heaters are used for thorough source outgassing. After loading, efficient charge conversion is achieved by heating the red phosphorus zone to evaporation temperatures, while cooling the white phosphorus reservoir to promote condensation of the P4 vapor. During growth, an adjustable temperature gradient is achieved using just a single bulk heater. With the heater in the red phosphorus zone, the crucible can be heated to a red phosphorus temperature of 190掳C (sufficiently low to avoid evaporation of red phosphorus during operation) and a white phosphorus temperature of 75-100掳C. Air cooling reduces the temperature in the white zone to the desired operating level. This system provides excellent thermal stability, even at white zone temperatures as low as 65掳C.

For rapid and reliable flux control, the gas flow is metered from the crucible to the cracking zone with an all-metal needle valve. Efficient conversion of P4 to P2 occurs in the high-conductance cracking zone. A 91制片厂Phosphorus Valved Cracker Temperature Controller is recommended for use with this source, as well as a 91制片厂SMC-II Automated Valve Positioner for reliable, automated control of the needle valve.

Performance and Benefits

The Valved Cracker for Phosphorus is a proven effective and safe alternative to the use of phosphine for MBE growth. Valved sources offer the precise Group V flux control needed for demanding quaternary GaInAsP materials, as well as efficient shut-off for the growth of arsenide/phosphide heterostructures with minimal intermixing (1%) between the layers.

The source鈥檚 valve mechanism makes it possible to quickly and reproducibly establish whatever beam equivalent pressure (BEP) is required to optimize growth parameters. Closing the valve prevents loss of source material during bakeout. Results from laboratories worldwide using this source demonstrate exceptional material quality and state-of-the-art electronic and optoelectronic devices.

Demonstrated results include:

• Red laser diodes in the GaInP/AlGaInP material system emitting at 630-670nm with high power output and good device lifetimes
• Resonant cavity light-emitting diodes in the AlGaInP system emitting at 660nm show high efficiency and long lifetimes. RCLEDs emitting at 1300nm show excellent spectral purity

This source has multiple heating zones that can either generate cracked or uncracked selenium flux while resisting the chemical attack from the corrosive vapor. The unrivaled convenience and flux control are maintained without depleting the source material via an all-metal needle valve. Excellent results have been reported producing blue/green LED and laser diode devices.

• Patented design with more than 50 in the field
• Provides flux modulation and on/off control
• Large source capacity
• Utilizes a nozzle for excellent flux uniformity and reduced material waste
• Prevents loss of source material during system bakeout
• Utilized by leading II-VI research groups worldwide with more than 50 in the field

The 91制片厂Valved Cracker for Selenium is used by leading II-VI research groups worldwide. Its multiple heating zones can be operated to generate a cracked or uncracked selenium flux. An all-metal needle valve regulates the gas flow from the crucible through the conductance tube to the growth module. The conductance tube is constructed of tantalum for resistance to chemical attack from selenium vapor.

With recent enhancements, the Mark V Valved Cracker for Selenium incorporates a nozzle that provides excellent flux uniformity and reduced material waste. This improvement in material utilization results in:

• Material cost savings
• Longer campaigns
• Less hazardous waste generation
• Reduced memory effects
• Lower particulate levels and flakin
• Reduced system window coating

The 91制片厂Valved Cracker for Selenium is available in 500cc and 1200cc sizes for compatibility with various MBE systems. The exit nozzle is customized to the specific MBE system for excellent flux uniformity across the wafer or platen. A 91制片厂SMC-II Automated Valve Positioner is recommended for use with this source for reliable, automated control of the needle valve.

Performance and Benefits

The 91制片厂Valved Source for Selenium offers convenience and flux control unrivaled by any standard source. Control over the growth process is optimized using a needle valve for nearly instantaneous flux modulations and complete flux shut-off. The source may be idled continuously at operating temperature without depleting the charge material. With mechanical flux control, rather than the thermal control used for conventional open sources, the charge capacity may be arbitrarily large without limiting the responsiveness of the source.

Benefits include:

• Longer growth campaigns
• Charge preservation during bakeout and idle periods
• More thorough charge outgassing
• Lower unintentional Group VI background in the system

Excellent flux stability and responsiveness have been demonstrated with the successful growth of blue/green light-emitting diodes and laser diodes based on ZnMgSSe/ZnSSe/ZnCdSe.

The patented 91制片厂Valved Cracker for Arsenic is the source that revolutionized solid source MBE. Used in hundreds of MBE systems worldwide, it is the industry standard arsenic source for R&D and production. The innovative design of the 91制片厂Valved Cracker provides the convenience of a gas source with the safety of a solid source. The solid arsenic is heated within the large capacity crucible to generate beam flux. A refractory metal needle valve regulates the gas flow into an independently heated cracking zone. Adjustments to the cracking zone temperature may be performed to generate either As4 or As2 beams.

• Patented design with nearly 1000 in the field
• Advanced flux modeling capability enables a custom designed nozzle based on the system geometry and use case
• Nozzle design optimizes material utilization and flux uniformity
• Mechanical flux control for near instantaneous response
• More economical to operate than a standard source

With recent enhancements, the Mark V Valved Cracker for Arsenic incorporates a nozzle that provides excellent flux uniformity and reduced material waste. This improvement in material utilization results in the following:

• Material cost savings
• Longer campaigns
• Shorter system cleaning time
• Less hazardous waste generation
• Reduced memory effects
• Lower particulate levels and flaking

Reduced system window coating the 91制片厂Valved Cracker for Arsenic is available in a range of sizes for compatibility with all MBE systems. In many cases, more than one size is offered to accommodate applications with high arsenic usage. The exit nozzle is customized to the specific MBE system for excellent flux uniformity across a wafer or a platen. A 91制片厂SMC-II Automated Valve Positioner is recommended for use with this source for reliable, automated control of the needle valve.

Performance and Benefits

The Valved Cracker for Arsenic optimizes control over the growth process by using a needle valve for near instantaneous flux modulations and complete flux shut-off. The source may be idled continuously at operating temperature without depleting the charge material. With mechanical flux control, rather than the thermal control used for conventional open sources, the charge capacity may be arbitrarily large without limiting the responsiveness of the source.

Demonstrated benefits include:

• More control over the growth process
• Greater productivity
• Longer growth campaigns
• Reduced As consumption
• More thorough charge outgassing
• Elimination of unintentional as incorporation into heterostructures
• Better use of in situ diagnostic tools

Achieve increased uptime and lower repair costs with Veeco’s ammonia-resisant, extended life sources. Available for temperatures up to 120掳C with ammonia partial pressures as high as 1×10-4 Torr. Substrate heaters are also available for temperatures up to 1200掳C and oxygen partial pressures of 1×10-4 Torr.

• Extended life for ammonia environments
• SUMO crucible available with optimal flux distribution and minimized depletion effects
• Ammonia partial pressures up to 1×10-4 Torr
• Temperatures up to 1200掳C
• More than 20 in the field

Using ammonia (NH3) as the nitrogen source is becoming increasingly more common due to the ability to achieve high growth rates and for its ease of control. Consequently, ammonia can dramatically reduce equipment lifetime. Due to hydrogen embrittlement, it is not uncommon for source and heater filaments to last only a few months. Therefore, equipment uptime is compromised, leading to shorter campaign lengths and high repair costs.

This source is a cost-effective solution that’s ideal for high vapor pressure materials. Hot-lip heating design reduces condensation at the crucible orifice, and heat-shielding enclosure enables optimal source responsiveness and stability in the temperature operating range of 100-750掳C.

• Cost-effective solution for low temperature evaporation with more than 400 in the field
• Single filament hot-lip heating to reduce condensation at the crucible orifice
• Proven performance
• Compatible with most MBE systems and custom UHV chambers

The Low Temperature Single Filament Source provides stable and consistent fluxes of high vapor pressure materials. Its performance below 750掳C surpasses conventional sources because of its low thermal mass. The source is enclosed in a heat-shielding package designed for optimal source responsiveness and stability in the operating range of 100-750掳C. Temperature stability is critical with high vapor pressure materials, since even a small temperature variation produces a dramatic change in the flux.

This source features a modified single filament design. It achieves hot-lip heating with a filament that uniformly heats the bottom portion of the crucible but includes extra filament density at the top to compensate for radiative heat loss at the orifice. Hot-lip heating eliminates material recondensation at the crucible orifice, which can lead to source occlusion and beam shadowing.

The Low Temperature Single Filament Source offers good performance and value for general purpose applications. For demanding applications, or when large source capacities are required, a Low Temperature Dual Filament or Low Temperature SUMO Source is recommended.

Performance and Benefits The Low Temperature Single Filament Source is precisely tailored to the demands of evaporating high vapor pressure materials.

Benefits include:

• Optimal performance at lower operating temperatures
• Rapid flux stabilization
• Excellent long-term flux stability
• Hot-lip heating to prevent condensation at the crucible orifice (proven with difficult materials like antimony, tellurium, and lead compounds)

This source uses two independent filaments to heat the crucible, primary and tip, providing enhanced heating control. The tip filament is operated in hot-lip mode to prevent condensation at the crucible lip. In addition, the heat-shielding enclosure enables optimal source responsiveness and stability in the temperature operating range of 100-750掳C.

• Patented design with more than 50 in the field
• Optimized for responsive performance at low operating temperatures
• Dual filament hot-lip heating to prevent condensation at the crucible orifice
• Excellent long-term flux stability with high vapor pressure materials

The 91制片厂Low Temperature Dual Filament Source for MBE uses two independent heaters to control the temperature variation along the length of the crucible. The primary heater filament heats most of the crucible. The tip filament heats just the mouth region of the crucible to compensate for the greater radiative heat loss in this area. The source is operated in hot-lipped mode to eliminate material recondensation at the crucible orifice, which can lead to source occlusion and beam shadowing.

The Low Temperature Dual Filament Source is enclosed in a heat-shielding package designed for optimal source responsiveness and stability in the operating range of 100-750掳C. Temperature stability is critical with high vapor pressure materials, since even a small temperature variation produces a dramatic change in the flux.

The Low Temperature Dual Filament Source is also available in the high-performance SUMO design. See the 鈥淟ow Temperature SUMO Source鈥� data sheet for further details.

Performance and Benefits

The Low Temperature Dual Filament Source is precisely tailored to the demands of evaporating high vapor pressure materials.

Benefits include:

• Optimal performance at lower operating temperatures
• Rapid flux stabilization
• Excellent long-term flux stability

Dual Filament 鈥渉ot-lip鈥� heating prevents condensation at the crucible orifice. This has been proven effective with a number of 鈥渄ifficult鈥� materials including antimony, tellurium, and lead compounds.

This source provides efficient material conservation and near instantaneous modulations for either cracked or uncracked flux while resisting the chemical attack from the corrosive vapor. The convenience and flux control are maintained without depleting the source material via a refractory metal needle valve. Excellent results have been reported producing blue/green LED and laser diode devices.

• Generates either cracked or uncracked S flux
• Provides flux modulation and on/off control
• Large source capacity
• Utilizes a nozzle for excellent flux uniformity and reduced material waste
• Prevents loss of source material during system bakeout
• Used by leading II-VI research groups worldwide with more than 30 in the field

The 91制片厂MBE Valved Cracker for Sulfur offers convenience and control unrivaled by any standard source. The large capacity refractory metal crucible is heated to generate a sulfur beam flux (consisting of Sn where n=8,7,6,5,3,2). Gas flow is regulated through a refractory metal needle valve into an independently heated cracking zone. The temperature of the cracking zone may be adjusted to generate either uncracked sulfur flux or a beam of smaller sulfur species. The cracking zone is constructed of quartz rather than a refractory metal due to sulfur鈥檚 corrosive nature.

With recent enhancements, the Mark V Valved Cracker for Sulfur incorporates a nozzle that provides excellent flux uniformity and reduced material waste. This improvement in material utilization results in:

• Material cost savings
• Longer campaigns
• Shorter system cleaning time
• Less hazardous waste generation
• Reduced memory effects
• Lower particulate levels and flaking
• Reduced system window coating

A 91制片厂SMC-II Automated Valve Positioner is recommended for use with this source for reliable, automated control of the needle valve.

This source is the best available source for non-valved evaporation of high vapor pressure materials, offering critical temperature stability. This is achieved by a dual filament heater tailored to a uniquely shaped crucible. This design also prevents condensation from forming at the crucible lip, preventing flux shadowing and source occlusion. An optional insert is also available to further restrict the back pressure in the crucible.

• Patented design with more than 175 in the field
• Versatile high-performance source for low temperature evaporation
• SUMO design combines excellent flux stability and uniformity with large charge capacity
• PBN crucible construction optimizes material quality
• Ideal source for organic materials

The patented Low Temperature SUMO庐 Source is the best available source for non-valved evaporation of high vapor pressure materials. The SUMO source is comprised of a dual filament heater tailored to a uniquely shaped crucible. The source is operated in hot-lipped mode to prevent flux shadowing and source occlusion caused by material recondensation at the crucible lip. The Low Temperature SUMO Source is enclosed in a heat-shielding package designed for optimal source responsiveness and stability in the operating range of 100鈥�750掳C.

Temperature stability is critical with high vapor pressure materials, since even a small temperature variation produces a dramatic change in flux. Heat radiated from the substrate manipulator sometimes makes it difficult to maintain a stable beam flux at very low source operating conditions. Due to the smaller orifice size, this effect is significantly reduced when using a SUMO source in place of a conical or cylindrical crucible.

Patented design with more than 175 in the field Versatile high-performance source for low temperature evaporation Dual filament hot-lip heating to prevent condensation at the crucible orifice SUMO design combines excellent flux stability and uniformity with large charge capacity PBN crucible construction optimizes material quality Ideal source for organic materials.

SUMO Crucible

The unique patented crucible features:

• A cylindrical reservoir for large charge capacity and minimized long-term depletion effects
• A small tapered orifice for optimal flux distribution
• An exit cone for excellent flux uniformity with minimal wasted material
• PBN construction for optimal material quality

An optional insert is available to restrict the crucible orifice size and thereby increase the back pressure in the crucible. This technique can improve the performance of very high vapor pressure materials, including those used as dopants. The insert is recommended particularly for sources which would be operated at temperatures of 300掳C or lower.

Low Temperature SUMO for Organics

The Low Temperature SUMO Source is well-suited for use with the high vapor pressure organic materials commonly used in organic light-emitting diodes (OLEDs) and electronic applications. Due to the low thermal conductivity of organics, stable beam fluxes are difficult to achieve with conventional evaporation sources. A Low Temperature SUMO source is the best solution for stable and uniform deposition of organics. For applications which require a collimated beam to maximize material usage and minimize blow-by, a 鈥渓onghorn鈥� SUMO crucible is available.

Performance and Benefits

The Low Temperature SUMO Source is precisely tailored to the demands of evaporating high vapor pressure materials.

Benefits include:

• Optimal performance at lower operating temperatures
• Large charge capacity
• Dual Filament 鈥淗ot-Lip鈥� heating to prevent condensation at the crucible orifice
• Long-term flux stability
• Minimal shutter transients
• PBN crucible construction for optimal material quality

Achieve increased uptime and lower repair costs with Veeco’s oxygen-resistant, extended life sources. Available for temperatures up to 1150掳C with oxygen partial pressures as high as 5 milliTorr. Substrate heaters are also available for temperatures up to 800掳C and oxygen partial pressures of 5 milliTorr.

• SUMO crucible available with optimal flux distribution and minimized depletion effects
• Oxygen partial pressures up to 5milliTorr
• Temperatures up to 1150掳C
• More than 20 in the field

Oxide material research has increased considerably over the years because of its importance in the IC industry and because of the wide variety of electronic and optical properties made possible using these materials.

Due to the corrosive nature of oxygen, performing thin-film research in an oxygen environment often presents equipment challenges. For example, it is common to thermally evaporate materials in an oxygen environment of 10-5 Torr or higher while maintaining the substrate temperature at 800掳C. The high oxygen partial pressure and temperature greatly reduces the lifetime of the heating elements in sources and substrate heaters. As a result, the equipment uptime is compromised, leading to shorter campaign lengths and high repair costs.

Using special oxygen-resistant materials, as opposed to traditional materials such as molybdenum and tantalum, it is now possible to operate Veeco鈥檚 innovative and proven sources and substrate heaters in high oxygen partial pressure environments. Oxygen-resistant sources are currently available from 91制片厂for temperatures up to 1150掳C with oxygen partial pressures as high as 5milliTorr. Substrate heaters are also available for temperatures up to 800掳C and oxygen partial pressures of 5milliTorr.