# US 7,746,118 B2 · Single electron based flexible multi-functional logic circuit and the transistor thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,118 B2 - Document ID: US7746118B2 - Status: Granted - Kind: B2 - Application number: 12/281,846 - Filed: 2007-09-11 - Published: 2009-10-08 - Granted: 2010-06-29 - Earliest claimed: 2006-12-19 - Assignees: Changbuk National University Industry-Academic Cooperation Foundation - Inventors: Jung Bum Choi; Cang Keun Lee; Sang Jin Kim; Jae Ho Hwang - Web page: https://patentgrep.com/patent/US7746118B2 ## CPC - H03K 19/20: characterised by logic function, e.g. AND, OR, NOR, NOT circuits (H03K19/003 - H03K19/01 take precedence) - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - H10D 30/402: {Single electron transistors; Coulomb blockade transistors} - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract The present invention relates to a flexible multi-functional logic circuit which switches a current direction to a serial or parallel direction using at least two single electron transistors (SETs) having the same pattern and as many field effect transistors (FETs) as the number of the single electron transistors and performs operations on multi-valued signals using Coulomb oscillation that is the unique characteristic of SET to enable conversion of a single logic circuit to four basic logic circuits of NAND, OR, NOR and AND gates and a device using the same. ## Claims ### Claim 1 A single electron based flexible multi-functional logic circuit comprising: first and second single electron transistors SET1 and SET2 respectively having side gates Gate1 and Gate2 and input voltage ports Vin1 and Vin2; a constant current source VD for supplying a predetermined current; a first field effect transistor FET1 for maintaining a predetermined drain voltage applied to the first and second single electron transistors SET1 and SET2 by the constant current source VD; at least a second field effect transistor FET2 for determining flow of current to the first and second single electron transistors SET1 and SET2; and two ports Port1 and Port2 for changing a current flow direction depending on whether the second field effect transistor FET2 is turned on or off. ### Claim 2 (depends on 1) The single electron based flexible multi-functional logic circuit according to claim 1, wherein the first and second single electron transistors SET1 and SET2 are connected in parallel with each other to construct a logic NOR circuit when the second field effect transistor FET2 is turned on. ### Claim 3 (depends on 1, 2) The single electron based flexible multi-functional logic circuit according to claim 1 or 2, wherein a voltage is applied to the side gates of the first and second single electron transistors SET1 and SET2 to control phases of Coulomb oscillations of the first and second single electron transistors by 180° to construct a logic AND circuit when the second field effect transistor FET2 is turned on. ### Claim 4 (depends on 1, 2, 3) The single electron based flexible multi-functional logic circuit according to any one of claims 1 to 3, wherein the first and second single electron transistors SET1 and SET2 are serially connected to construct a logic NAND circuit when the second field effect transistor FET2 is turned off. ### Claim 5 (depends on 1, 2, 3) The single electron based flexible multi-functional logic circuit according to any one of claims 1 to 3, wherein a voltage is applied to the side gates of the first and second single electron transistors SET1 and SET2 to control phases of Coulomb oscillations of the first and second single electron transistors by 180° to construct a logic OR circuit when the second field effect transistor FET2 is turned off. ### Claim 6 (depends on 1) The single electron based flexible multi-functional logic circuit according to claim 1, wherein the second field effect transistor FET2 is a depletion transistor. ### Claim 7 (depends on 1) The single electron based flexible multi-functional logic circuit according to claim 1, wherein the side gates Gate1 and Gate2 change a phase difference of Coulomb oscillations by 180°. ### Claim 8 A single electron based flexible multi-functional logic circuit comprising: an active region defined in an insulating layer formed on a semiconductor substrate such that the active region has a pair of quantum dots opposite to each other; a pair of semiconductor regions symmetrically arranged in such a way that each of tunnel junctions is formed at the outer sides of the quantum dots and is positioned between the semiconductor regions; two ports formed on the active region, having the quantum dots placed between them; a control gate formed between the quantum dots; a pair of side gates formed in such a manner that their ends are respectively located on the quantum dots; and a gate oxide layer formed between the active region and the control gate, wherein impurity ions are implanted into the side gates and the active region to dope the side gates and define ion-implanted semiconductor regions. ### Claim 9 (depends on 8) The single electron based flexible multi-functional logic circuit according to claim 8, wherein the pair of side gates, the control gate and the two ports are simultaneously formed on the same plane using electron beam lithography.