Method for locally highly doped and connected semiconductor structures that are solar cells or precursors to solar cells

Abstract

The invention relates to a method for local high-doping and contacting of a semiconductor structure which is a solar cell or a precursor of a solar cell and has a silicon semiconductor substrate (1) of a base doping type. The high-doping and contacting is effected by producing a plurality of local high-doping regions of the base doping type in the semiconductor substrate (1) on a contacting side (1a) of the semiconductor substrate and applying a metal contacting layer (7) to the contacting side (1a) or, if applicable, one or more intermediate layers wholly or partially covering the contacting side (1a), to form electrically conductive connections between the metal contacting layer (7) and the semiconductor substrate (1) at the high doping regions. It is important that the method comprises the following steps: A) producing a layer structure covering the contacting side (1 a) of the semiconductor substrate, comprising a doping layer (3), which contains a dopant of the base doping type and is in the form of a layer of amorphous silicon or a layer of amorphous silicon carbide having a carbon content less than 10 at. % and a reflective layer (4), which at least in the wavelength range between 800 nm and 1200 nm is constructed with a refractive index nR smaller than the refractive index nHs of the semiconductor substrate, wherein the doping layer (3) lying in the layer sequence closer to the contacting side (1 a) is constructed as the reflective layer (4); B) local heating of layer structure and the surface lying thereunder of the semiconductor substrate at a plurality of zones to form local high-doping regions, wherein the local heating is effected such that at each of the locally heated regions a melt mixture of at least the doping layer (3) and a portion of the semiconductor substrate is formed locally on the contacting side (1 a), and on solidification of the melt mixture a high doping region (6) more strongly doped by at least the dopant of the doping layer (3) is formed in the semiconductor substrate (1) on the contacting side (1 a), and applying a metal contacting layer (7) to form an electrically conductive connection between semiconductor substrate (1) and contacting layer (7) at the high-doping regions.

Description

technical field [0001] The invention relates to a method according to the general concept of claim 1 for locally highly doped and switched-on semiconductor structures which are solar cells or solar cell precursors and which have a base doping type of silicon semiconductor substrate. Background technique [0002] In the case of photovoltaic solar cells based on silicon semiconductor substrates, numerous methods have been developed to achieve high efficiencies in the conversion of incident electromagnetic radiation into electrical energy on the one hand and cost-effective industrial production on the other hand. Especially in solar cells in which the emitter and the pn structure of the carrier pairs resulting from this separation are constructed on or in the front area of ​​the solar cell for light incidence, the electrical contacting of the base region is usually made by means of an arrangement on the rear side This is done by means of a metal connection layer which is elect...

AI Technical Summary

Problems solved by technology

This structure, which allows backside contacting for high efficiency, requires several additional photolithographic steps in fabrication besides the additional diffusion for highly doped regions, making industrial implementation of this solar cell structure impractical. or at least means very high cost

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