Laser‐fired contact optimization in c‐Si solar cells

Abstract

In this work we study the optimization of laser-fired contact (LFC) processing parameters, namely laser power and number of pulses, based on the electrical resistance measurement of an aluminum single LFC point. LFC process has been made through four passivation layers that are typically used in c-Si and mc-Si solar cell fabrication: thermally grown silicon oxide (Si0 2 ), deposited phosphorus-doped amorphous silicon carbide (a-SiC/H(«)), aluminum oxide (A1 2 0 3 ) and silicon nitride (SiN^/H) films. Values for the LFC resistance normalized by the laser spot area in the range of 0.65-3 mil cm 2 have been obtained.

Microscale Characterization of Surface Recombination at the Vicinity of Laser-Processed Regions in c-Si Solar Cells

“…The normalized PL loss reveals that the reduction in passivation efficiency is much lower for the sample with the capping layer for the same spot diameter. In a previous work [6], we show that the effective surface recombination velocity at the laser processed surface of SiC x /Al 2 O 3 -passivated c-Si is significantly lower than that measured at the laser processed surface of Al 2 O 3 -passivated c-Si. The obtained PL profiles suggest that the lower laser-induced impact in the spot surroundings observed in the samples with SiC x capping layer would be partially responsible of their better performance.…”

“…A very promising and industrially feasible approach to fabricate these advanced solar cell architectures is laser processing. In this approach, a laser beam fires the surface of a solar cell, to create, for instance, local heavily doped regions [2], [3], or point-like contacts, the so-called laser fired contacts (LFCs) [4]− [6].…”

“…In particular, we have studied LPRs in silicon carbide/aluminum oxide (SiC x /Al 2 O 3 )-and Al 2 O 3 -passivated c-Si wafers. As recently reported, when Al 2 O 3 is used as passivation layer, the alumina film acts as Al (p-type) dopant source and then the laser processing can be used for both creating selective emitters (in n-type c-Si wafers) [17] or laser fired contacts (LFCs) (in p-type c-Si wafers) [6].…”

Ohmic contacts fabricated on moderately doped p-type GaAs by sputtering deposition and a laser-firing process

“…Laser fired contacts (LFC) have been successfully applied in other studies to form ohmic contacts. [11][12][13] This work is divided in two stages. In the first stage, we investigated how Zn sputtering power conditions influence the electrical characteristics of metal-semiconductor contacts.…”

Experimental determination of base resistance contribution for point-like contacted c-Si solar cells using impedance spectroscopy analysis

“…A second approach consists of a metal deposited on top of the dielectric that is laser fired through it leading to the so-called Laser Firing Contacts (LFC). Typically this technique is done with Aluminum to create base contacts on p-type substrates [5][6], but recently a metal stack containing Antimony has also demonstrated its viability for the creation of base contacts on n-type wafers [7]. Finally, the laser radiation can impinge directly on the dielectric film that works as dopant source.…”