AVS 51st International Symposium
    Nanometer-scale Science and Technology Thursday Sessions
       Session NS2-ThA

Invited Paper NS2-ThA5
Progress Towards Silicon Nanowire-based Complementary Logic

Thursday, November 18, 2004, 3:20 pm, Room 213D

Session: Nanowires II
Presenter: T.S. Mayer, Penn State University
Authors: T.S. Mayer, Penn State University
Y. Wang, Penn State University
T.-T. Ho, Penn State University
K.-K. Lew, Penn State University
L. Pan, Penn State University
E.C. Dickey, Penn State University
J.M. Redwing, Penn State University
Correspondent: Click to Email
There has been considerable interest in bottom-up assembly of semiconductor nanowires for their application in future logic, memory, and sensor circuits. In this talk, we will present results of recent research showing that p- and n-type dopants can be intentionally incorporated into silicon nanowires (SiNWs) during template-directed vapor-liquid-solid (VLS) growth to produce complementary field effect devices. In this work, Au metal particles electrodeposited within 80-nm diameter pores of anodized alumina templates serve to catalyze SiNW growth at temperatures of 500° C using 10% silane (SiH@sub 4@) in H@sub 2@ as the silicon gas source, trimethylboron (TMB) as the p-type dopant, and phosphine (PH@sub 3@) as the n-type dopant. Transmission electron microscopy (TEM) studies of individual SiNWs show that approximately two-thirds of the SiNWs are single crystal, while the remaining one-third are bicrystals. Additionally, the surfaces of all of the p- and n-type SiNWs investigated were free of amorphous layers that were observed previously when diborane was used as a p-type dopant gas. Secondary ion mass spectroscopy (SIMS) on bundles of SiNWs indicate that B- and P-concentrations increase with increasing TMB:SiH@sub 4@ or PH@sub 3@:SiH@sub 4@ gas ratios between 10@super -5@ and 10@super -2@, and can exceed 10@super 19@ cm@super -3@ for the highest gas ratios investigated. Gate-dependent conductance measurements of individual B- and P-doped SiNWs show complementary characteristics that are consistent with depletion mode device operation, where the threshold voltage is adjusted by changing the dopant:SiH@sub 4@ gas ratio during VLS growth. Independent measurements of four-point resistivity also show a clear decrease in resistivity with increasing TMB:SiH@sub 4@ or PH@sub 3@:SiH@sub 4@ gas ratios. These results confirm that p- and n-type dopants can be effectively incorporated during SiNW synthesis to produce complementary field effect devices in the same material system.