Studies of diffused boron emitters: saturation current, bandgap narrowing, and surface recombination velocity

The emitter saturation current density, J/sub 0/ was measured on diffused boron emitters in silicon for the case in which the emitter surface is passivated by a thermal oxide and for the case in which Al/Si is deposited on the emitter surface. The oxide-passivated emitters have a surface recombination velocity, s, which is near its lowest technologically achievable value. In contrast, the emitters with Al/Si on the surface have surface recombination velocities which approach the maximum possible value of s. From the J/sub 0/ measurements, the apparent bandgap narrowing as a function of boron doping was found. Using this bandgap narrowing data, the surface recombination velocity at the Si/SiO/sub 2/ interface was extracted for surface boron concentrations from 3*10/sup 17/ to 3*10/sup 19/ cm/sup -3/.>