Silicon-based tunneling field-effect transistor with elevated germanium source formed on (110) silicon substrate

Si-based tunneling field-effect transistors (TFETs) with elevated Ge source were fabricated on Si(110) substrate. The in situ B-doped Ge (Ge:B) source grown on Si(110) has a substitutional B concentration up to 7.8 X 10(20) cm(-3), that is more than one order of magnitude higher than that in Ge grown on Si(100) under the same growth conditions. Ge:B epitaxy on (110) and (100) Si is discussed. The TFET with elevated Ge source formed on Si(110) has a subthreshold swing of 85 mV/decade, which is a substantial improvement over that of the control TFET formed on Si(100). This is attributed to the high B doping concentration in the Ge: B(110) source as well as the band gap narrowing effect. (C) 2011 American Institute of Physics. [doi:10.1063/1.3579242]