Solar Applications: CIGS Absorber

Overview: The CIGS layer stack is most commonly deposited on Soda Lime Glass (SLG); however, many companies are also looking at lighter, more flexible substrates such as polyimide or metal foils. Mustang is an industry leader in the Roll-to-Roll processing of flexible substrates. Mustang can supply a Roll-to-Roll or in-line solution for R&D or production with the best price to performance ratio in the solar industry. Mustang uses in-line metrology for process control and optimization to insure that the CIGS absorber layer meets customer specifications for efficiency.

Production Equipment

The SprintFlex
Designed for free-span deposition of thin films up to 40cm wide (Pilot Production Scale)
The Orion Series
Designed for deposition of thin films on substrates 40cm to 2m wide (Production Scale)
The Horizon
Horizontal in-line sputtering system optimized glass substrates
The Horizon V
Vertical In-line sputtering system with turn around, optimized glass substrates
Mustang designs & manufactures custom systems to meet customer specifications.

Research & Development Systems

The Mini Solar
Designed for R&D or low volume production, the Mini Solar is available with a variety of deposition sources.
The Orion Complete
Designed for free-span deposition of multiple thin films up to 40cm wide. A great R&D solution, this unit has 7 multi-source deposition zones, allowing users to deposit all PV layers in a continuous roll-to-roll system.

There are several key issues such as yield, material cost and capital cost that critically affect the manufacturing of the CIGS absorber layer. The production yield depends on many factors, especially on uniformity of deposition. Uniformity over a large area is very critical because a single faulty device can severely affect the performance of the entire module. Superior device performance is achieved when the junction is matched to the solar spectrum by increasing the bandgap, increasing the open circuit voltage (Voc). The increase in Voc also benefits the manufacturing process and device properties by reducing the number of scribes for the monolithic integration of the cells into modules, reducing the top and bottom electrode thickness, lowering the temperature coefficient at maximum power, and making the cell less sensitive to fluctuations. Effective control of deposition parameters is critical in this aspect.

Custom Process Solutions:  CIGS customers globally continue to innovate and evolve the processes and intellectual property of this dynamic industry. Mustang Solar offers customized vacuum deposition solutions tailored to individual customer processes. Our design teams work closely with customer process teams under strict confidentiality to create robust systems using our configurable deposition platforms to achieve high yield, high throughput manufacturing solutions for both pilot and full production environments.

NREL Process Licensing Partnership

Mustang Solar is pleased to offer a range of CIGS deposition systems optimized for NREL licensable processes. With the cooperation of NREL process teams, Mustang Solar has designed both sputtering and co-evaporation solutions to bring the NREL CIGS experience to production scale.


Selenium – Two of the most challenging aspects of CIGS manufacturing relate to selenium deposition campaigns and containment of this corrosive material within the deposition system. Mustang Solar’s design experience increases up time with longer campaigns and minimizes the impact of selenium vapor on adjacent process, pumping hardware and in chamber components.

  • Compositional sputtering of Cu,In,Ga
  • Compositional sputtering of Cu,In,Ga in the presence of Se at high temperature
  • Elemental Evaporation of Cu,In,Ga,Se
  • Co-Evaporation of Cu,In,Ga,Se


  • 200mm to 2,000mm flexible substrate platforms
  • Single-side or dual-side touch of substrates with or without Interleaf

Glass – Standard platforms for a wide range of substrate sizes

  • Single or multiple substrate deposition across deposition zones up to 3.5 meters
  • Vertical and Horizontal deposition orientation

Deposition Sources

Mustang Solar integrates sources from leading global suppliers as well as develops specialized sources when commercial solutions are not available. Planar & Rotatable Magnetron, Thermal evaporation, E-beam, IonBeam and hybrids. Mustang works with customers to identify the optimal deposition solution balancing uptime, reliability and performance.