Patented One Step Integrated Cell Connection

One Step Integrated Cell Connection XSEM

Fig.1: SEM cross section of a P1i patterning structure showing the CIGS cell stack applying a 3-layer backelectrode and the P1-laser groove filled with insulating ink

The significant advantage of the one step integrated cell connection is displayed in the reduction of the front end processing from typically 11 processing steps to finally 5, see the schema Fig.2 below.

The major benefits of this technology are:

significant cost reduction by saving processing steps
better front end process control through simplified process sequence, see Fig. 4 below
custom designed cell layout production in campains enabled just by loading different recipes in one processing step
increase of active module area (efficiency) by reducing the spacing between the patterning lines. This is enabled by:
- eliminating mounting & demounting of the modules in between the different steps of integrated series connection (dependance of line spacing on adjustment accuracy is eliminated)
- self-adjustment of the patterning lines to each other in one processing system
better low light behavior of the solar modules due to a nearly ideal cell insulation (parasitic shunts between the cells - which always occur by conventional integrated series connection through the conductive CIGS-layer - are eliminated)
CIGS doping by e.g. sodium is not restricted any more by parasitic shunt effects on patterning P1 => higher module efficiency through accurate doping adjustment

P1i Scheme

Process Simplification CIGS through one step integrated cell connection

Fig.2: Significant reduction of front end processing steps by applying the patented one step integrated cell connection

advanced integrated cell connection after completed cell processing

Fig.3: Schematic drawings of the two offered approaches P1i & Piz to innovative cell integration. P1i offers all the advantages of patterning after CIGS formation and buffer deposition; P1z in addition offers all the advantages of one step cell integration;

reduction of process interaction through one step integrated cell connection

Fig.4: Most process interactions of the front end processing of CIGS solar modules are undesired, because a targeted change of process parameters in one processing step enforces complex and expensive re-adjustment of the interacting processing steps.

Therefore a reduction of process interactions is very important for an accurate adjustment at an optimum of the process parameters and for a stable processing line. The proposed innovations do reduce those process interactions to a minimum.

SolCIS