A Korea-US joint research team has disclosed an investigation result on improving the Lanthanum doped transistor, which is a most promising next-generation nanotransistor for its power reduction can be easily achieved by adjusting the threshold voltage.
Prof Yoon-Ha Jeong of POSTECH Electrical Engineering Department and Sematech of US have identified the relationship between the Lanthanum doped field effect transistor dipole and its radio frequency (RF) performance, and proposed a model that can improve the device characteristics.
The study has been presented as, "Impact of Dipole-Induced Dielectric Relaxation on High-frequency Performance in La-Incorporated HfSiON/Metal Gate nMOSFET", at the International Electron Device Meeting (IEDM), and it will improve the processing of RF integrated circuits by solving the degradation of the transistor characteristics. The CMOS nano scale transistors, which are embedded in cell phones and CPU's of computers, showed large performance deviation from the design target due to uncontrollable RF characteristics.
Especially, the voltage gain loss with the increasing frequency has primarily affected the nanotransistor design from accurate prediction, and the precise fabrication has not been possible.
The research team has identified the cause of degradation as the dielectric relaxation of dipole induced by Lanthanum, and developed a precise model for circuit design application.
The new model can predict the potential degradation condition of nanotransistor, and enable correct design, hence the device processing, developing time and cost can be saved greatly.
Dr. Chang Yong Kang of Sematech commented, "This study has achieved a significant technological innovation in performance analysis and modeling of ultra high speed logic and RF circuits".
The research has been funded by Ministry of Education, Science and Technology, World Class University (WCU), Information Technology Convergence Engineering (ITCE) and BK21 program and by Ministry of Knowledge Economy National Center for Nanomaterials Technology(NCNT) program.