Impact Ionization Nanowire Transistor with Multiple-Gates, Silicon-Germanium Impact Ionization Region, and Sub-5 mV/decade Subtheshold Swing

We report the first demonstration of an Impact Ionization nanowire multiple-gate field-effect transistor (I-MuGFET or I-FinFET). Excellent subthreshold swing of sub-5 mV/decade at room temperature was achieved. The multiple- gate structure enhances the impact ionization rate in the fin or nanowire channel, reduces the breakdown voltage and improves device performance. A silicon-germanium (SiGe) impact ionization region (I-region) is integrated on a Si or SiGe nanowire to enhance performance and reduce the breakdown voltage. A record low breakdown voltage of -4.75 V is achieved for SiGe nanowire device. Complementary pair of I-FinFETs were realized. The lower electron and hole impact-ionization threshold energy of SiGe greatly enhances the drive current of n- and p-channel devices by 3 and 2.4 folds, respectively.