Singulus Technologies has launched its new ‘GENERIS’ PVD inline sputtering system for heterojunction (HJ) solar cells. The system is suited for challenging transparent conductive oxides (TCO) layers like ITO and AZO hat can produce HJ cells with conversion efficiencies of more than 22%, as well as reduce manufacturing costs. New system will be presented at SNEC 2017 in Shanghai, China.
Sputter damage to the amorphous silicon passivation layers is caused by plasma photons in the range of 2.5 to 4.15eV, which causes carrier lifetime degradation in HJ cells. Charge carrier mobility and electron density need to be optimized to minimize free carrier absorption in the ITO film. To reach high-efficiencies, the hetero-interface state density should be minimalised.
The newly developed GENERIS PVD system is a horizontal inline sputter tool designed for special requirements in photovoltaic high efficiency cell production. On top of the silicon layers, an antireflective TCO is deposited by physical vapor deposition (PVD) and the charge collection is made by a screen-printed metallic contacts. A Heterojunction cell performance of 22.3% was achieved in cooperation with a research institute, according to the company. The deposited ITO layers exhibit excellent optical transmittance. Charge carrier mobility and electron density are optimized to minimize free carrier absorption in the ITO film. Sputter damage to the amorphous silicon passivation layers did not occur.
The GENERIS PVD system is ideally suited for challenging transparent conductive oxides layers like ITO and AZO to match the key requirements of heterojunction cell technology.
With the GENERIS PVD sputtering system, contact layers can be deposited on the front and rear of the Si wafers without the need to turn the wafers between coating processes and without vacuum interruption. Also full area metal coatings, e.g. Ag, can be deposited within the same system. By using rotatable sputtering cathodes, highest target utilization is achieved and offers lowest production costs. The GENERIS PVD system with a modular chamber setup provides a throughput range from 2600 wph up to 5200WPH. Different metallic layers like Al, Cu, NiV, etc. are available. The GENERIS PVD is using an inline process in which the Si wafers are transported on specially designed carriers, providing edge isolation simultaneously. The carrier return system is located below the machine under clean environmental conditions. Different automation options for loading and unloading are selectable.
April 2017 onwards.