A CMOS Biochip for Electrical Detection of DNA with an Embedded Current Amplifier Circuit

This paper presents a CMOS biochip for DNA detection with an embedded current amplifier circuit by using self-assembly multilayer gold nanoparticles (AuNPs). The biochip is fabricated by a TSMC 0.35 mum 2P4M standard CMOS process and post-CMOS micromachining processes. On each measuring spot, there is a pair of electrodes with a gap distance of 350 nm. Through a self-assembly process between suspended gold nanoparticles and the thiol-modified end of probe oligonucleotide strand, multilayer AuNPs on the nanogap surface can be established. An approximate 1000-fold increase in electric current between the nanogap of multilayer AuNPs over monolayer AuNPs is an indication of the presence of target oligonucleotide strand. After integrating the electrodes with an embedded current amplifier, the electric current of multilayer AuNPs can be amplified to the level of 1 mA and it is easily measured by a commercial Volt-ohm-Milliammeter without any expensive and complex instruments