In production of thin-film solar cells one of the most efficient solar light absorbing materials is compound Cu(In,Ga)Se₂ (CIGS). High efficiency of single solar cells (SC) using this material achieved by this time evoke many researchers to concentrate their effort on development of industry-scale technology of monolithically integrated modules manufacture. Record-high conversion efficiency (~19.9%) is characteristic of CIGS SC having area only ~ 0.4 cm². As of today this efficiency is achieved only through technology of simultaneous co-evaporation of four elements – Cu, In, Ga and Se. The required final result of CIGS films technology is manufacture of film layer having thickness within 1-2 μ, having polycrystalline large-grain structure of chalcopyrite type and definite crystallographic orientation. Also certain thickness profile in relation to concentrations of Cu/(In+Ga) and Ga/(In+Ga) must be provided, with Selene content closely following formula Cu(In,Ga)Se_2.. To meet these requirements very complicated instrumentation and process control procedures are needed.

Monolithically integrated module of solar cells (MIM CS), as basic product of thin-film solar power engineering, is predominantly a glass substrate, on which dozens and hundreds of single SCs are combined as one battery in the form of narrow and long strips. In a way similar to microelectronics, where increase of chip and wafer-substrate size dramatically reduces manufacturing cost of devices, in MIM SC manufacture, as size of substrate-carrier and strip width drops, the cost of manufacture of one watt of power generated by solar light also drops.

Modern technologies of plasma-chemical amorphous silicon deposition on glass substrates, brought from LCD production, allowed to start production of MIM SC with substrate size of 2.2х2.6м (5.7 м²). Still, though dimensions are so impressive, this type of MIM SC allows to generate only 515 W of electric power under standard lighting conditions due to low quantum efficiency of amorphous silicon as an absorbing material.

As opposed to amorphous silicon, CIGS material is much more efficient as solar light absorber. But co-evaporation technology is so complicated in what concerns reproducibility, that is practically unacceptable for large-size substrates.

Meanwhile, LC displays’ production technology, besides well advanced plasma-chemical deposition of uniform amorphous silicon films on large area, also uses deposition processes of transparent conductive layers of type ITO and ZnO:Al by reactive magnetron sputtering methods. In this case film composition is provided by, first, correct composition and sputtering modes for initial metal alloy target (like alloy In-Sn for ITO and Zn-Al for ZnO:Al), and, second, correct control of argon and oxygen supply to discharge zone.

The idea to apply reactive sputtering for deposition of CIGS films was taken as a principle of the successfully completed project at Izovac company.

The resulting technology allowed to consistently obtain reproducible CIGS films having quality necessary for manufacture of MIM SC.

CIGS films formed by reactive magnetron sputtering method demonstrate parameters that allow to produce thin-film MIM SC with level of efficiency not lower than average in modern production of similar devices. As the method has no major limitations in scaling, one can assume it will take adequate place in commercial manufacturing in the nearest future.

In addition to the technology of CIGS films by Izovac was designed complex of equipment for production of solar cells.