US 11,415,643 B2Granted

Amplification using ambipolar hall effect in graphene

AssigneeTexas Instruments Incorporated

InventorsBaher S. Haroun, Arup Polley, Srinath M. Ramaswamy

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Abstract

An amplifier includes a graphene Hall sensor (GHS). The GHS includes a graphene layer formed above a substrate, a dielectric structure formed above a channel portion of the graphene layer, and a conductive gate structure formed above at least a portion of the dielectric structure above the channel portion of the graphene layer for applying a gate voltage. The GHS also includes first and second conductive excitation contact structures coupled with corresponding first and second excitation portions of the graphene layer for applying at least one of the following to the channel portion of the graphene layer: a bias voltage; and a bias current. The GHS further includes first and second conductive sense contact structures coupled with corresponding first and second sense portions of the graphene layer. The amplifier also includes a current sense amplifier (CSA) coupled to the GHS. The CSA senses current output from the GHS.

Claims15

Dependent claims

An amplifier, comprising:

a graphene Hall sensor (GHS), wherein the GHS comprises:
a graphene layer formed above a substrate;
a dielectric structure formed above a channel portion of the graphene layer;
a conductive gate structure formed above at least a portion of the dielectric structure above the channel portion of the graphene layer for applying a gate voltage;
first and second conductive excitation contact structures coupled with corresponding first and second excitation portions of the graphene layer for applying at least one of the following to the channel portion of the graphene layer:
a bias voltage;
and a bias current;
and
first and second conductive sense contact structures coupled with corresponding first and second sense portions of the graphene layer;
a current sense amplifier (CSA) coupled to the GHS, wherein the CSA senses current output from the GHS, and wherein an output of the CSA corresponds to an amplification of the applied gate voltage;
and
a bias magnetic source for applying a bias magnetic field to the GHS;
wherein an amplification based on the applied gate voltage and the CSA output that results using the amplifier is expressed by the following equation:
A
V
=
μ
⁢
⁢
WC
R
⁢
BV
bias
⁢
L
⁢
(
qn
0
)
2
+
(
C
Q
⁢
V
T
)
2
where:
Av is the amplification limit;
μ is the mobility of the graphene layer;
W is the width of the excitation portions of the graphene layer;
L is the width of the graphene layer including both excitations portions;
CR is the series capacitance;
B is the bias magnetic field;
Vbias is the bias voltage;
q is the electron charge;
no is the residual charge density;
CQ is the quantum capacitance;
and
VT is the constant temperature voltage.

51 more elements

A method, comprising:

employing a graphene Hall sensor (GHS), wherein the GHS comprises:
a graphene layer formed above a substrate;
a dielectric structure formed above a channel portion of the graphene layer;
a conductive gate structure formed above at least a portion of the dielectric structure above the channel portion of the graphene layer;
first and second conductive excitation contact structures coupled with corresponding first and second excitation portions of the graphene layer;
and
first and second conductive sense contact structures coupled with corresponding first and second sense portions of the graphene layer;
applying a gate voltage to the conductive gate structure;
applying at least one of a bias voltage and a bias current to the channel portion of the graphene layer via the first and second conductive excitation contact structures;
and
sensing current output from the GHS using a current sense amplifier (CSA) coupled to the GHS, wherein an output of the CSA corresponds to an amplification of the applied gate voltage;
and
applying a bias magnetic field to the GHS;
wherein an amplification based on the applied gate voltage and the CSA output that results using the employing step, the applying steps, and the sensing step is expressed by the following equation:
A
V
=
μ
⁢
⁢
WC
R
⁢
BV
bias
⁢
L
⁢
(
qn
0
)
2
+
(
C
Q
⁢
V
T
)
2
where:
Av is the amplification limit;
μ is the mobility of the graphene layer;
W is the width of the excitation portions of the graphene layer;
L is the width of the graphene layer including both excitations portions;
CR is the series capacitance;
B is the bias magnetic field;
Vbias is the bias voltage;
q is the electron charge;
no is the residual charge density;
CQ is the quantum capacitance;
and
VT is the constant temperature voltage.

52 more elements

A method, comprising:

applying a gate voltage to a conductive gate structure of a graphene Hall sensor (GHS), wherein the GHS comprises:
a graphene layer;
a dielectric structure formed above a channel portion of the graphene layer, wherein the conductive gate structure is formed above at least a portion of the dielectric structure above the channel portion of the graphene layer;
first and second conductive excitation contact structures coupled with corresponding first and second excitation portions of the graphene layer;
and
first and second conductive sense contact structures coupled with corresponding first and second sense portions of the graphene layer;
applying at least one of a bias voltage and a bias current to the channel portion of the graphene layer via the first and second conductive excitation contact structures;
applying a bias magnetic field to the GHS;
and
sensing current output from the GHS using a current sense amplifier (CSA) coupled to the GHS, wherein an output of the CSA corresponds to an amplification of the applied gate voltage;
wherein an amplification based on the applied gate voltage and the CSA output that results using the employing step, the applying steps, and the sensing step is expressed by the following equation:
A
V
=
μ
⁢
⁢
WC
R
⁢
BV
bias
⁢
L
⁢
(
qn
0
)
2
+
(
C
Q
⁢
V
T
)
2
where:
Av is the amplification limit;
μ is the mobility of the graphene layer;
W is the width of the excitation portions of the graphene layer;
L is the width of the graphene layer including both excitations portions;
CR is the series capacitance;
B is the bias magnetic field;
Vbias is the bias voltage;
q is the electron charge;
no is the residual charge density;
CQ is the quantum capacitance;
and
VT is the constant temperature voltage.

49 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/657,281Filed 18 Oct 2019 · us provisional application
Priority: 6 Dec 2018
Published: US 2020/0182950 A111 Jun 2020
Granted: 16 Aug 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G01R 33/07
Using galvano-magnetic devices: hall effect devices
H03F 15/00
Amplifiers using galvano-magnetic effects not involving mechanical movement
H10N 52/101
Hall-effect devices: semiconductor Hall-effect devices
H10N 52/80
Hall-effect devices: constructional details