ИСТИНА

The ability of Indium Tin Oxide (ITO) and Indium Fluorine Oxide (IFO) thin films deposited by pyro-sol method to form rectifying or ohmic contact to n- and p-type silicon have been investigated, studying the depend-ence of open-circuit voltage UOC of TCO/Si junction on the most important deposition parameters: substrate tempera-ture and carrier gas composition (Ar+O2). ITO/(pp+)Si, ITO/(nn+)Si, IFO/(pp+)Si and IFO/(nn+)Si heterostructures were produced. The open circuit voltage UOC of these structures strongly depended on the deposition temperature T and carrier gas composition (Ar+O2). IFO_500 film deposited at high temperature ~500°C in Ar+O2(2%) revealed rectifying junction on p-Si with UOC[IFO/(pp+)Si] ~590 mV and nearly ohmic contact to n-Si with UOC[IFO/(nn+)Si]~3 mV. Decreasing T down to 440°C resulted in degradation of both rectifying/ohmic properties, giving UOC[IFO/(pp+)Si]~300 mV (film IFO_300). Conversely, ITO deposited at low temperatures ~400°C in O2 me-dia formed rectifying junction with n-Si (UOC[ITO/(nn+)Si]~560 mV) and nearly ohmic contact with p-Si (UOC[ITO/(pp+)Si]~10 mV). Raising T degraded ITO/Si junction rectifying/ohmic properties. QSS-UOC method re-vealed that IFO_300 film passivates shallow n+ emitter (150 Ω/sq) with great loss in fill factor (-6.6%) as compared with negligible loss for IFO_500 film (-0.4%). It is concluded that IFO_500 better deactivates pinholes in emitter. So-lar cells having ITO/(nn+)Si/IFO and IFO/(pp+)Si/ITO structures were processed with efficiencies more than 14%.