Control of channel doping concentration for enhancing the sensitivity of 'top-down' fabricated Si nanochannel FET biosensors.
The sensitivity of 'top-down' fabricated Si nanochannel field effect transistor (FET) biosensors has been analyzed quantitatively, as a function of the channel width and doping concentration. We have fabricated 130-, 150-, and 220 nm-wide Si FET channels with 40 nm-thick p-type silicon-on-insulator (SOI) layers doped at 8 x 10(17) and 2 x 10(18) cm(-3), and characterized their sensitivity in response to the variation of surface charges as hydrogen ion sensors within buffer solutions of various pH levels. Within the range of channel width and doping concentration investigated, the pH sensitivity of Si channels is enhanced much more effectively by decreasing the doping concentration than by reducing the channel width, which suggests a practical strategy for achieving high sensitivity with less effort than to reduce the channel width. Similar behavior has also been confirmed in the immunodetection of prostate specific antigen (PSA). Combined with excellent reproducibility and uniformity of the channel structure, high controllability of the doping concentration can make the 'top-down' fabrication a very useful approach for the massive fabrication of high-sensitivity sensor platforms in a cost-effective way.
Park
Chan Woo
CW
Biosensor Research Team, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700, Korea. chanwoo@etri.re.kr
Ahn
Chang-Geun
CG
Yang
Jong-Heon
JH
Baek
In-Bok
IB
Ah
Chil Seong
CS
Kim
Ansoon
A
Kim
Tae-Youb
TY
Sung
Gun Yong
GY
D015374:Biosensing Techniques / Q000295:instrumentation*; D004560:Electricity; D006863:Hydrogen-Ion Concentration; D049329:Nanostructures / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013057:Spectrum Analysis; D013997:Time Factors; D014173:Transistors, Electronic
D012825:Silicon