RAPID THERMAL ANNEALING OF THIN DOPED AND UNDOPED SPIN-ON GLASS-FILMS

Rapid thermal annealing (RTA) was investigated for curing doped and un doped spin-on glass films deposited onto silicon substrates. The annea led undoped spin-on glass (SOG) films present an important densificati on of the layers as a function of temperature and a reduction in the i nterfacial state density. The possibility of using rapid thermally ann ealed spin-on doped glass (SOD) films as a doping source as well as a surface passivation layer was investigated. The results show that the combination of spin-on film (after dilution of the solution with metha nol) deposition and RTA can produce shallow lightly doped emitters. Sh eet resistances lower than 150 Omega square are easily reached. Moreov er, the minority-carrier diffusion length is improved owing to the get tering effect induced by phosphorus diffusion. The use as a passivatio n layer of the SOG or the remaining SOD oxide film makes this techniqu e favourable for applications such as the fabrication of solar cells.