120 likes | 250 Views
Hybrid Molecular MOSFET Chemical Sensor. 12.11.02 - Group Members: Robert Anderson, Fesaha Gebrehiwot, Stephanie Padilla, and Ari Vogel - Project Advisor: Dr. Trevor Thornton. Abstract.
E N D
Hybrid Molecular MOSFET Chemical Sensor 12.11.02 - Group Members: Robert Anderson, Fesaha Gebrehiwot, Stephanie Padilla, and Ari Vogel - Project Advisor: Dr. Trevor Thornton Hybrid Molecular-Semiconductor Chemical Sensor
Abstract This project aims to develop a Hybrid Molecular MOSFET chemical sensor that is highly integrated, inexpensive, and versatile. The sensor consists of a polarizable molecular monolayer that adheres to an underlying CMOS-compatible integrated circuit. The molecular monolayers are designed in such a way that their physical structure changes after exposure to the chemical of interest. The change in physical structure leads to a change in their electrical polarization, which is detected by a sensitive transistor immediately below the monolayer. A simple pH sensor was realized in order to demonstrate the working principles of the HM-FET. Hybrid Molecular-Semiconductor Chemical Sensor
Theory The HM-FET chemical sensor is based on a fully depleted Silicon-on-Insulator (SOI) MOSFET. Due to the buried oxide in an SOI structure, the substrate voltage can be used in place of a conventional gate voltage. This allows the active surface to be free of any metal contacts. The channel is 150nm thick, and therefore the threshold voltage of the device can easily be controlled by the charge accumulated on the surface of the device. As the charge increases at the surface, additional carriers are available to allow greater current flow. Also, the native oxide of the silicon channel can be used as a bonding film for attaching the monolayer to the device. Hybrid Molecular-Semiconductor Chemical Sensor
Sensor Applications The HM-FET has a wide range of envisioned applications. ·DNA decoder ØCrime scene investigation ØMedical applications ·Chemical sensor ØPlanetary exploration ØDetection of harmful natural gases ØDetection of biological or chemical agents ØpH sensor Hybrid Molecular-Semiconductor Chemical Sensor
Conclusion From the experimental and simulated results, a working pH sensor was constructed. The pH sensor demonstrates the working principles of an HM-FET by observing shifts in the threshold voltage when a charge is present at the surface of the device. The diverse applications of the HM-FET along with their benefits are evident, and therefore the team recommends that this design project be further pursued. The HM-FET can be used to make the world a safer and more educated place, and the technology is very close to being available to the public. Hybrid Molecular-Semiconductor Chemical Sensor
Atlas Device Model Hybrid Molecular-Semiconductor Chemical Sensor
Matched Simulated vs. Experimental Hybrid Molecular-Semiconductor Chemical Sensor
Linear Relationship Vth Hybrid Molecular-Semiconductor Chemical Sensor
Experimental (From B. Reddy) Hybrid Molecular-Semiconductor Chemical Sensor