Thermal Management for Optoelectronics and Microelectronics

  • Exceptional flatness and dimensional tolerance control.
  • Superior thermal conductivity compared to competitive technologies.
  • Excellent CTE stability till over 400C.
  • Consistent plating quality even on narrow features.

Spectra-Mat’s unique technology to infiltrate copper

in an highly homogeneous sintered tungsten matrix guarantees the homogeneity of thermal conductivity of the tungsten copper material along the three axes. The CTE of tungsten copper is stable from room temperature to over the melting temperature of solders. The fine machining capabilities and the dedicated plating line assure consistency and homogeneity of final parts in any shapes.

Application Semiconductor Spectra-Mat Solution CTE (ppm @ 25C) Thermal Conductivity W/(k2m)
IR Power Semiconductor Laser GaAs W/Cu 90/10 spacers 6.2 201
UV Semiconductor Laser GaN W/Cu 92/8 spacer 5.8 188
HB LEDs GaN W/Cu 92/8 wafer 5.8 188
RF Amplifiers GaAs W/Cu 90/10 Base 6.2 201
Aerospace RF Amplifiers GaAs Mo/Cu 85/15 Base 6.8 154
MW Amplifiers GaN W/Cu 92/8 Base 5.8 188
At 25 C, CTE of GaAs is 6.5 ppm/K and of GaN is 3.2 ppm/k.

Solutions for High Power Semiconductor Lasers:

The superior thermal conductivity of Spectra-mat’s spacers enables the management of the highest level of power of semiconductor lasers.

Solutions for Optical Benches:

The brazing capabilities of tungsten copper to ceramics enable the manufacturing of optical benches where high power semiconductor lasers are couples to lenses and other optical components.

Solutions for HB LEDs:

In the latest generation of HB LEDs, the reduction of production costs can be achieved by employing wafer level packaging, therefore tungsten copper plated wafers (from 2″ to 6′) are the enabling solutions to guarantee an efficient thermal management at reasonable production costs

Solutions for fiber lasers:

The combiner inside a fiber laser has to withstand a very high thermal load. Tungsten copper combiner can guarantee a quick transfer of the heat from the fiber. Due to their optical grade surface and gold plating, the tungsten copper combiner does not absorb any light.

Solutions for RF and MW amplifiers (MMICs):

GaN and GaAs amplifiers are expanding the realm of their applications. Tungsten copper and moly copper flat bases, flanges and ma¬chined bases with pockets and pass-through guarantee a continuous flow of heat out of the amplifiers.

Tungsten Copper Spacers for Semiconductor Lasers

  • Flatness: 0.3 μm/mm.
  • Edge radius better than 15 μm.
  • Dimensional tolerances: ±10 μm.
  • Surface roughness: as low as 0.03 μm Ra.
  • AuSn layers with different compositions and thickness.

The requirements for more powerful semiconductor lasers

The requirements for more powerful semiconductor lasers both in pulsed and CW mode challenge the ability of traditional thermal management materials to quickly and efficiently dissipate heat. Contrary to injection molding technology, Spectra-Mat’s unique technology to infiltrate copper in an highly homogeneous sintered tungsten matrix guarantees the homogeneity of thermal conductivity of the tungsten copper submounts along the three axes, a very important requirement for multi diodes lasers bars. The superior homogeneity of Spectra-Mat’s tungsten copper material keeps the CTE stable from room temperature to over the soldering temperatures of the laser bars.

W weight CTE Thermal conductivity
W 90% Cu 10% 6.2 ppm/K @ 25C 201 W/(m*K)
W 85% Cu 15% 6.8 ppm/K @ 25C 210 W/(m*K)
W 80% Cu 20% 7.4 ppm/K @ 25C 219 W/(m*K)
W 75% Cu 25% 8.0 ppm/K @ 25C 228 W/(m*K)
At 25 C, CTE of GaAs is 6.5 ppm/K and of GaN is 3.2 ppm/k.

The recent developments of our dedicated refractory

composite plating process assure a stable flatness better than 0.3 μm per mm, minimizing the “smile” effect in laser diodes arrays. The final lapping of the bulk surface can enable different grades of surface roughness (better than 0.03 μm Ra) to optimize adhesion to the solder.

The tungsten copper submounts can be supplied plated for use of AuSn preform or with patterned or unpatterned AuSn metallization with AuSn solder of different compositions. AuSn layers with possible metal barrier layers can be deposited by sputtering, evaporation or jet process.

Edge radius quality is better than 15 μm, enabling the proper cooling of the emitting surface of the laser diode as well as avoiding any slipping of the laser diode at high temperature. The tight dimensional tolerances fit the strictest requirements for semiconductor lasers stacks.

Cathodes For Ion Gas Lasers


  • Despite the success of the solid state and semiconductor lasers, ion gas lasers are still widely used in a variety of industrial and scientific applications because of their superior characteristics in terms of coherence of the laser beam.
  • Since the beginning of the development of ion gas lasers, Spectra-Mat contributed to the success of the technology.
  • Since then Spectra-Mat has manufactured thousands of high quality and highly reliable cathodes.
  • Spectra-Mat Patent N° 3514661.



  • Robust structure
  • Spirals diameters ranging from 0.13″ up to over 1.00″.
  • Excellent parallelism of spirals
  • Reliable welding of Mo legs
  • High purity raw materials for impregnants guaranteeing stable and high electrons emission
  • Proven long life in ion gas laser operating conditions
  • Cathodes are working excellently in Ar, Xe, Kr and HeCd gasses and their mixtures
  • No outgassing

Cathodes for Lamps

by leveraging the expertise in dispenser cathodes for microwave tubes

Spectra-Mat contributed to the development of high performances flash lamps, arc lamps and gas discharge devices by supplying cathodes of different shapes (circular with a tip and able to accommodate a stem) and sizes. Moreover, the material used for cathodes in high vacuum tubes guarantees an extremely low outgassing level with no carbonated gasses that might create black spots on the glass walls of the lamps.

Over the time Spectra-Mat cathodes showed a sizeable resistance to ion bombardment in different gas mixtures and pressures in lamps and gas discharge devices, enabling a longer lifetime of the devices. The large variety of different impregnants together with their high purity enables the optimization of the cathode performances.

  • Long lifetime
  • Different impregnants available
  • Resistance to ion bombardment
  • Low outgassing
  • Different shapes and sizes
  • High open porosity surface

The most important feature of Spectra-Mat cathodes is the high ratio of open pores on the highly homogeneous emitting surface, that provides a path for Ba to exit on the surface to increase the electrons emission.

Dispenser Cathodes for X-Ray Tubes

The new generation of x-rays systems based on micro-focus technology

is enabling not destructive, faster and more accurate real time quality controls and inspection in the production lines of many electronic devices such as batteries and printed circuits boards as well as in the food and drug industries, The spot size diameter of the x-ray beam for the micro focus systems is below 10 microns: small diameter, tip shaped dispenser cathodes are enabling this micrometric diameter of the x-ray beam. that might find also important applications in the medical science. The dispenser cathodes for x-rays tubes can have different shapes and sizes down to 0.01″ (0.25 mm) as shown below.

Tip Diameter Unpotted X-ray Cathodes Potted X-ray Cathodes Potted With Sleeves X-ray Cathodes Potted With Sleeves and Base X-ray Cathodes
  1126X Series 1126HX Series 1126HS Series 1126HB Series
0.096 (2.5 mm) 112-600 112-610 112-620 112-630
0.020 (0.5mm) 112-602 112-612 112-622 112-632
0.039 (1 mm) 112 604 112-614 112-624 112-634
0.059 [1.5 mrn] 112-606 112-616 112-626 112-636
HT.:3 Series – Emitter I Bcdv / Heater / Sleeve /

Spectra-Mat is supplying the dispenser cathodes for x-rays tubes in different configurations: abase, a potted heater and sleeves can be added to match the customer’s needs. In ;Any case, the dispenser cathodes will work at around 1000 C when a power of few Watt is applied to the heater.

The lifetime of dispenser cathodes inside x-rays tubes has been proven over 20000 hours thanks to the uniform distribution of pores over the emitter surface. The lifetime of dispenser cathodes is definitively longer than pure tungsten filaments, making dispenser cathodes a financially viable solution for x-rays inspection system whose maintenance time needs to be minimized because they operate in 24 hours production environment.

  • Proven long life.
  • Standard and scandate mixes available.
  • Tip size down to 0.01″ (0.25 mm).
  • OsRu coating.
  • Dispenser cathodes with bases available.
  • Engineering support to design the suitable cathode geometry.

Dispenser Cathodes

Over the last 50 years, Spectra-Mat’s technology for dispenser cathodes contributed to the latest advancements of the modern microwave, linear accelerators and x-rays tubes industry. Spectra-Mat duly controls all production processes from tungsten powder sieving till temperature test of the dispenser cathodes. Our Engineering Department supports the developments of new cathodes structures and shapes together with the possible addition to other components to dispenser cathodes inside the gun while our quality assurance procedures guarantee the full traceability of all the components.

  • Sizes: diameter from 0.010″ (0.25 mm) to over 10.00″ (254 mm)
  • Tungsten densities: from 50% to 84%
  • Standard impregnants: 532, 411, 311, 612
  • Scandate Mixes: 532X, 411X, 311X, 612X
  • Coatings available: OsRu, OsW, Ir
  • Machined Tolerance: +0.0002″ (+0.005 mm)
  • Proven current density in CW mode: up to 20 A/cm2
  • Proven current density in pulsed mode: up to 120 A/cm2
  • Proven operating lifetime: over 150000 hours
  • Hollow cathodes, assembled guns and UHV potted > Coatings available: OsRu, OsW, Ir heaters available

Cathodes for TWTs:

small diameter, high performance dispenser cathodes are produced in relatively large volume.

Cathodes for Klystrons and Gyrotron:

Spectra-Mat has been the leading manufacturer for large diameter and high performance dispenser cathodes.

Cathodes for magnetron:

long hollow dispenser cathodes are available for magnetron use.

Cathodes for Ion Thrusters and TeraHz sources:

Cathodes for Ion Thrusters and TeraHz sources: dispenser cathodes are enabling new applications such as electric propulsion and of THz sources for telecom, scientific and industrial applications.

Cathodes for x-rays:

small diameter dispenser cathodes with tips of different geometries are enabling new x-rays application.

Cathodes for neutron generators:

Dispenser cathodes with particular shapes are available.

Cathodes for industrial application:

Dispenser cathodes are enabling new applications such as ebeam polymerization and sterilization.

Cathodes for linear accelerators:

Spectra-Mat supplied the largest diameter dispenser cathodes for linear accelerators for scientific and medical use.