Schubert M.C.,Fraunhofer Institute for Solar Energy Systems |
Habenicht H.,Centrotherm Photovoltaics AG |
Warta W.,Fraunhofer Institute for Solar Energy Systems
IEEE Journal of Photovoltaics | Year: 2011
Photoluminescence imaging is able to provide quantitative information about carrier lifetime in silicon wafers. Recently, this technique has been applied to measure the distribution of iron and chromium point defects in p-type silicon. In this paper, we summarize the state of the art and extend the impurity analysis by photoluminescence imaging with the detection of the boron-oxygen defect. Solar cells from p-type Czochralski silicon material are mostly limited by this defect, but its impact may also be significant for multicrystalline silicon. For the presence of several metastable defect species, we demonstrate the preparation of a specific state of the metastable defects with appropriate conditions for temperature and illumination and show that the respective impurity concentrations can be determined in parallel. We complete the analysis by discussing the effects of lateral carrier diffusion on the measurement result. © 2011 IEEE. Source
Centrotherm Photovoltaics AG | Date: 2011-12-16
The application describes an apparatus and a method for the thermal treatment of substrates, in particular thin film substrates for photovoltaic applications. The apparatus comprises at least one substrate carrier for supporting a substrate, a heating unit having at least one heating element for heating a substrate located on the substrate carrier and at least one heating element carrier for supporting the at least one heating element. The heating element carrier is designed to allow a local change in distance between the substrate carrier and the heating element, so as to be able to provide locally different heating intensities. In the method such a change in distance is carried out during the thermal treatment.
Centrotherm Photovoltaics AG | Date: 2012-08-01
A device for doping, deposition or oxidation of semiconductor material at low pressure in a process tube, is provided with a tube closure as well as devices for supplying and discharging process gases and for generating a negative pressure in the process tube. A closure of the process chamber that is gas tight with respect to the process gases and the vacuum tight seal of the end of the tube closure are spatially separated from each other in relation to the atmosphere and are arranged on a same side of the process tube in such a manner that a bottom of a stopper, sealing the process chamber, rests against a sealing rim of the process tube and the tube closure end is sealed vacuum tight by a collar, which is attached to the process tube and against which a door rests sealingly.
Centrotherm Photovoltaics AG | Date: 2013-11-11
A substrate holder having a plate element for receiving a substrate. The plate element comprises at least one recess in a first side of the plate element as well as a plurality of spacers in the at least one recess, at least one opening, which is fluidly connected to the recess and which may be connected to an external gas delivery/exhaust unit, at least one notch or channel, which radially surrounds the recess, at least one opening, which is fluidly connected to the notch or channel and may be connected to an external gas delivery/exhaust unit, a circumferential web, which radially surrounds the recess and is located between the recess and the notch or channel, and circumferential contact surfaces for the substrate, wherein a first circumferential contact surface is formed on the upper side of the web and radially surrounds the recess, such that a substrate abutting against the first contact surface forms an enclosed chamber with the recess, and a second circumferential contact surface, which radially surrounds the notch or channel.
Centrotherm Photovoltaics AG | Date: 2015-08-12
A method and an arrangement for providing chalcogens as thin layers on substrates, in particular on planar substrates prepared with precursor layers and composed of any desired materials, preferably on substrates composed of float glass, is achieved by forming an inlet- and outlet-side gas curtain for an oxygen-tight closure of a transport channel in a vapour deposition head, introducing an inert gas into the transport channel for displacing atmospheric oxygen, introducing one or more substrates to be coated, the substrates being temperature-regulated to a predetermined temperature, into the transport channel, introducing a chalcogen vapour/carrier gas mixture from a source into the transport channel at the vapour deposition head above the substrates and forming a selenium layer on the substrates by PVD at a predetermined pressure, and removing the substrates after a predetermined process time has elapsed.