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2005
Conference Paper
Titel
Low temperature back contact for high efficiency silicon solar cells
Abstract
We present a novel structure for backside passivation of silicon solar cells that enhances light trapping and provides a good electric contact. The advantage of this structure is the low process temperature of 220 °C. The key idea is to use different material compositions for surface passivation and light trapping. A double layer of intrinsic and boron doped amorphous silicon acts as backside passivation while an amorphous silicon nitride film enhances the reflectivity. A laser firing process forms the contacts allowing for low contact resistances without applying photolithography. Due to the fact that the maximum process temperature is 220 °C, this process bypasses expensive high temperature steps and is suitable for the use in devices which are sensitive to high process temperatures. With the novel backside structure, we reach open circuit voltages V(ind oc) <= 667 mV, short circuit currents J(ind sc) >= 39 mA/cm2 and conversion efficiencies eta <= 20.1 %.
Author(s)