Method for manufacturing a compound film

Abstract

A method for manufacturing a compound film comprising a substrate and at least one additional layer is disclosed. The method comprising the steps of depositing at least two chemical elements on the substrate and / or on the at least one additional layer using depositions sources, maintaining depositing of the at least two chemical elements while the substrate and the deposition sources are being moved relative to each other, measuring the compound film properties, particularly being compound film thickness, compound-film overall composition, and compound-film composition in one or several positions of the compound film, comparing the predefined values for the compound film properties to the measured compound film properties, and adjusting the deposition of the at least two chemical elements in case the measured compound film properties do not match the predefined compound film properties.

Description

RELATED APPLICATION[0001]This is a U.S. national phase application under 35 U.S.C. § 371 of International Application No. PCT / EP2007 / 059600 filed Sep. 12, 2007.TECHNICAL FIELD[0002]The present invention is related to a method for manufacturing a compound film comprising a substrate and at least one additional layer, the compound film satisfying predefined compound film properties, in particular being predefined values for compound-film thickness, compound-film overall composition and compositional profile, the latter being defined as a compound-film composition as a function of a position on or in the compound film. More particularly, the present invention is related to a method for measuring physical parameters of thin films, where the measurement takes place during or after film growth and where the measurement results are used for controlling film deposition processes. The invention also relates to a method for deposition of one or several thin films using vacuum deposition proce...

AI Technical Summary

Problems solved by technology

Standard solar cell technology today is based on crystalline or multi-crystalline silicon absorbers, for the production of which a comparatively high amount of material and energy is required, which in turn limits the production cost potential.

However, in a continuous-processing deposition system, like a roll-to-roll or in-line deposition system, an end point in the above sense is never reached and a deposition process is not stopped once a coating is completed.

The known teaching does not allow measuring material gradients in the CIGS layer, or controlling all evaporation sources when arranged in sequences such as Ga—Cu—In—Ga, for example.

This treatment destroys the sample and is therefore not suited for non-destructive deposition-process control.

However, if the atoms of one species in the film stem from more than one deposition source, typically from a second, similar deposition source, e.g. as it is depicted in FIG. 3 (b), in which a second A-source 12, depositing a material A, is present, then the film overall-composition and thickness measurement performed by a measurement device 10 does not allow separating the contributions from the two similar A-sources.

Therefore, it is not clear, which of the A-sources needs corrective action, and source control is not possible for all deposition sources.

However, as described above, when a second Ga source (or any other second similar source) is used, individual control of two similar deposition sources is no more possible with merely a thickness and overall-composition measurement.

As described above, as soon as one material is deposited by more than one deposition source before an overall-thickness and composition measurement is performed, the control problem occurs.

Since known measurement devices are heat-sensitive and since metal evaporation sources have to be operated at temperatures in the vicinity of 1000° C. or above, evaporation-source blocks cannot be placed close to each other because room is required for protection of the measurement devices from material deposition and heat radiation.

Hence, deposition machines can become very large and complicated, and the film stack may cool down while moving through the measurement zone before reaching the following evaporation-source block.