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US 9,000,505 B2Granted
Quantum electro-optical device using CMOS transistor with reverse polarity drain implant
AssigneeTexas Instruments Incorporated
InventorsHenry L. Edwards, Tathagata Chatterjee, Robert C. Bowen
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Abstract
A CMOS IC containing a quantum well electro-optical device (QWEOD) is disclosed. The QWEOD is formed in an NMOS transistor structure with a p-type drain region. The NLDD region abutting the p-type drain region forms a quantum well. The QWEOD may be fabricated with 65 nm technology node processes to have lateral dimensions less than 15 nm, enabling possible energy level separations above 50 meV. The quantum well electro-optical device may be operated in a negative conductance mode, in a photon emission mode or in a photo detection mode.
Claims1
A method comprising
- providing a p-type substrate;
- forming a gate dielectric layer on a top surface of the substrate;
- forming a gate on a top surface of the gate dielectric layer;
- forming an n-type source region in the substrate adjacent to and on one side of the gate;
- forming an n-type quantum well region in the substrate adjacent to the gate on an opposite side of the gate from the source region;
- and
- forming a p-type drain region in the substrate abutting the quantum well region on an opposite side of the quantum well region from the gate;
- wherein the method further comprises the step of forming a p-type halo region with a doping density between 1·1017 and 1·1018 cm−3 in the substrate under the gate and abutting the quantum well region;
- in which a width of the quantum well region is less than 15 nanometers;
- in which the step of forming the quantum well region is performed such that a doping density of the quantum well region is above 1·1019 cm−3;
- in which a first electron energy state in the quantum well region is separated from a second electron energy state in the quantum well region by more than 50 meV;
- in which the step of forming a p-type drain region further comprises the steps of:
- forming offset spacers on a lateral surfaces of the gate;
- forming gate sidewall spacers on lateral surfaces of the offset spacers;
- and
- ion implanting a set of p-type dopants into the substrate to form the drain region such that a lateral boundary of the drain region is defined on one side by a boundary of the gate sidewall spacers;
- and
- in which the step of forming an n-type quantum well region is performed concurrently with forming n-type lightly doped drain (NLDD) regions in an NMOS transistor.
15 more elements
Dependencies are inferred from the claim text.