Effect of Arrangement of Input Gates on Logic Switching Characteristics of Nanodot Array Device

Mingu JO  Yuki KATO  Masashi ARITA  Yukinori ONO  Akira FUJIWARA  Hiroshi INOKAWA  Yasuo TAKAHASHI  Jung-Bum CHOI  

IEICE TRANSACTIONS on Electronics   Vol.E95-C   No.5   pp.865-870
Publication Date: 2012/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E95.C.865
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Fundamentals and Applications of Advanced Semiconductor Devices)
single electron,  nanodot,  logic gate,  dot array,  Coulomb blockade,  

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We developed a flexible-logic-gate single-electron device (SED) in which logic functions can be selected by changing the voltage applied to the control gate. It consists of an array of nanodots with multiple inputs and multiple outputs. Since the gate electrodes couple capacitively to the many dots underneath, complicated characteristics depending on the combination of the gate voltages yield a selectable logic gate when some of the gate electrodes are used as control gates. One of the important issues is how to design the arrangement of nanodots and gate electrodes. In this study, we fabricated a Si nanodot array with two simple input gates and two output terminals, in which each gate was coupled to half of the nanodot array. Even though the device had a very simple input-gate arrangement and just one control gate, we could create a half-adder function through the use of current maps as functions of the input gate voltages. We found that the nanodots evenly coupled capacitively to both input gates played an important role in getting a basic set of logic functions. Moreover, these results guarantee that a more complicated input-gate structure, in which each gate evenly couples many nanodots, will yield more complicated functions.