Deposition of Buffer Layers on CIGS Solar Cells using TFS 1200 Atomic Layer Deposition (ALD) System by Beneq

Topics Covered

Overview
Atomic Layer Deposition Improving Efficiency of CIGS Solar Cells
Beneq ALD Technology Replacing Conventional Cadmium Sulfide Buffer Layer
Atomic Layer Deposition and Cadmium-Free Buffer Layers
TFS 1200 Thin Film System for Atomic Layer Deposition

Overview

Beneq Oy, based in Finland, is a supplier of equipment and coating technology for global markets. Beneq turns innovations into success by developing applications and equipment for cleantech and renewable energy fields, especially in glass, solar and emerging thin film markets. Coating applications include optics, barriers and passivation layers, as well as energy generation and conservation. Beneq also offers complete coating services. Beneq's coating applications are based on two enabling nanotechnology platforms: Atomic Layer Deposition (ALD) and aerosol coating (nHALO® and nAERO®).

Atomic Layer Deposition Improving Efficiency of CIGS Solar Cells

One of the most promising cells today is copper-indium-gallium-diselenide (CIGS). Atomic layer deposition (ALD) can be used to improve the efficiency of CIGS solar cells by more than 1 percentage point. This is achieved by depositing a dense and conformal zinc oxysulfide Zn(O,S) buffer layer.

Beneq ALD buffer layer for CIGS solar cells

Using ALD conveniently eliminates the only liquid phase deposition step, chemical bath deposition (CBD), from the process flow, which in turn simplifies production routines and significantly reduces cost. The TFS 1200 Thin Film System from Beneq is designed for in-line buffer layer deposition on CIGS. It can coat 1200 × 1200 (mm) panels at a throughput of 12 panels per hour and 100,000 m2 per year, equivalent to a total of 12 MWp per year. In an off-line configuration the throughput can be doubled.

Beneq ALD Technology Replacing Conventional Cadmium Sulfide Buffer Layer

Beneq ALD technology enables replacing the conventional cadmium sulfide (CdS) buffer layer with one with a higher band gap energy and light transmission, thus resulting in a more than 1 percentage point increase in unit efficiency. With ALD, it is possible to adjust and optimize the oxygen/ sulfur (O/S) ratio of the film type for the CIGS panel. The intrinsic properties of ALD coatings, conformal and dense, enable enhanced blocking of pinholes in the CIGS cells.

Atomic Layer Deposition and Cadmium-Free Buffer Layers

ALD offers a manufacturer of CIGS solar cells the opportunity to introduce cadmium-free buffer layers, which means less of a load on the environment and less stringent in- house material safety routines. ALD is a dry coating process, which means there is no excessive water handling, no toxic effluents and no need for waste water purification. In addition, Beneq ALD equipment can be seamlessly integrated into the production line, alongside other vacuum deposition steps, resulting in negligible exposure of the substrate to atmospheric gases.

TFS 1200 Thin Film System for Atomic Layer Deposition

The Beneq TFS 1200 is an ALD processing module that is integrated into CIGS evaporation or rapid thermal processing (RTP) selenization lines. Deposition time for a 30 nm thick Zn(O,S) buffer layer is less than 5 min. ALD is more compact and less expensive than conventional CBD-CdS buffer layer processes.

More information about the TFS 1200 is available on the TFS 1200 equipment page.

Source: Beneq

For more information on this source please visit Beneq

Date Added: Jan 14, 2011 | Updated: Jun 11, 2013
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