Specmat, Inc

The Room Temperature Wet Chemistry Growth (RTWCG) technology is a novel technology for growing highly uniform amorphous SiOx layers into silicon substrates. It can be broken down into two kinds of applications: as a chemical etchant and as a SiOx growth chemistry. For etching applications, the RTWCG formulation is adjusted to maximize the competitive SiOx etch rate so that it exceeds the oxide growth rate. For SiOx growth applications, the RTWCG formulation’s SiOx growth rate is optimized to exceed the competitive oxide etch rate. By varying the SiOx growth rate and/or the competitive etch-back rate, RTWCG SiOx growth solutions can be formulated to create SiOx thicknesses that range from no oxide to up to Angstrom (Å) per a certain constant substrate etch-back. In PV, the RTWCG etch technology can be utilized in various ways such as: dead layer etching, surface etching for selective emitter applications, and as a junction isolation process. The SiOx growth technology can be used to improve the optical properties of solar cells, to mitigate PID, and to increase passivation when used in, for instance, a SiNx/SiOx stack. For the photovoltaic (PV) industry, the technology can be applied to, either or both, the front and rear side of the solar cell to yield the following: o Front side silicon nitride (SiNx)/SiOx passivation and anti-reflection stack; o Front side SiOx passivation and anti-reflection coating (ARC); o Rear side parasitic emitter etch for junction isolation; o Rear side SiOx passivation layer growth; o Rear side SiOx optical layer; o Diffusion barrier layer. The following cell architectures for both N-type and P-type substrates: o Passivated emitter and rear totally diffused (PERT); o Passivated emitter and rear cell (PERC); o Passivated emitter and rear local back surface field (PERL); o Inter-digitated back contact cell (IBC); o Bi-facial.