Abstract:
We study for the first time the effect of nanowire thickness and doping concentration on the
electrical characteristics of single crystal and polycrystalline silicon nanowire biosensors. For
nanowire thicknesses of 100 nm and 75 nm, a plausible sub-threshold slope around 100
mV/decade for a viable biosensor operation only achieve if doping concentration is 2×1016/cm3
or below both for single crystal and poly Si nanowires. For a 50nm nanowire thickness a
relatively wide doping concentration range with a maximum doping up to 4×1017/cm3 choose
for biosensor design while maintaining decent sub-threshold characteristics. The widest range
of doping concentrations choose for 25nm and 10nm nanowire thickness with a maximum
doping up to 1018/cm3 while maintaining a promising sub-threshold slope around 95
mV/decade for a viable biosensor design using single crystal and polycrystalline silicon
nanowires. In general poly Si NW shows inferior characteristics than single crystal Si NW.
However, for 10nm Si NW single crystal & poly Si NW show same sub-threshold slopes at all
doping densities. Considering the fact that spacer etch process provides the cheapest & mass
manufacturable platform for biosensor fabrication using poly Si material in comparison to the
available single crystal platforms. It decides from this work that poly Si NW biosensor with Si
thickness ≤ 10nm is the possible commercial route of sensor fabrication.
Description:
This thesis submitted in partial fulfillment of the requirements for the degree of B.Sc in Electrical and Electronic Engineering of East West University, Dhaka, Bangladesh.