Transcript Slide 1
Single-electron Devices Speaker: Qiaoyan Yu [email protected] ECE423 12-16-2006 Agenda Milestone Motivations New characteristics Single-electron transistor (SET) Challenges Conclusions 2 Milestone In 1909, Millikan first illustrated the manipulation of single electrons. In 1985, Dmitri Averin & Konstantin Likharev proposed single-electron transistor. In 1987, Theodore Fulton & Gerald Doald at Bell lab fabricated and demonstrated SET. 3 Motivation Power consumption challenges high performance and high density chip design Faster and more information processing resulting in generating more heat flux Reduce the corresponding charge per bit! Single-electron Device!!! 4 SED new characteristics Exploit the quantum effect of tunneling Charge doest not flow continuously Control and measure the movement of single electron Instead in a quantized way Extremely high charge sensitivity High precise for charge measurement 5 Single-electron transistor (SET) Architecture Equivalent circuit Operation principle I-V curve SET VS. MOSFET 6 Architecture Tunnel junctions q island Source +q1 Vb V2 V1 -q1 +q2 C1 gate Drain -q2 C2 Cg Vg 7 Equivalent circuit 8 Operation principle 9 Operation principle 10 Operation principle 11 I-V curve 12 SET vs. MOSFET Structure Size Periodic vs. not periodic Sensitivity Coulomb blockade vs. electron diffusion Threshold voltage & source-drain current Extremely small vs. large (although scaled down) Main physical principle Two tunneling barrier vs. inversion channel High vs. low (10000X) Power Low vs. high 13 SED challenges Difficult to precisely control the device implementation Characteristic of the device varies significantly from location to location Suffer from “offset charges” Randomly fluctuation of control signal 14 Conclusions Because of natural small dimension, SED is a potential solution for continue silicon scaling. It is not clear that SET replaces FET. It is certain that quantum properties of electrons will be crucial in the design of electron devices. Electron beam lithography and scanning probe techniques offer the best prospects for the future. Some more esoteric techniques based on atomic particle deposition and colloid chemistry may also provide some benefits. 15 The End Thank You! Any questions? 16