# US 11,906,291 B2 · Method of calculating thickness of graphene layer and method of measuring content of silicon carbide by using XPS

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,906,291 B2
- Document ID: US11906291B2
- Status: Granted
- Kind: B2
- Application number: 17/145,966
- Filed: 2021-01-11
- Published: 2021-12-02
- Granted: 2024-02-20
- Earliest claimed: 2020-05-26
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Eunkyu Lee; Yeonchoo Cho; Sangwon Kim; Kyung-Eun Byun; Hyunjae Song; Hyeonjin Shin
- Web page: https://patentgrep.com/patent/US11906291B2

## CPC

- G01B 15/02: for measuring thickness
- C01B 32/182: Graphene
- G01N 23/2208: all measurements being of a secondary emission, e.g. combination of SE measurement and characteristic X-ray measurement
- G01N 23/2273: Measuring photoelectron spectrum, e.g. electron spectroscopy for chemical analysis [ESCA] or X-ray photoelectron spectroscopy [XPS]
- H10D 64/0111: {to Group IV semiconductors}
- H10D 64/62: Electrodes ohmically coupled to a semiconductor
- H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects}
- B82Y 35/00: Methods or apparatus for measurement or analysis of nanostructures
- G01N 2223/085: photo-electron spectrum [ESCA, XPS]
- G01N 2223/61: thin films, coatings
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

A method of calculating a thickness of a graphene layer and a method of measuring a content of silicon carbide, by using X-ray photoelectron spectroscopy (XPS), are provided. The method of calculating the thickness of the graphene layer, which is directly grown on a silicon substrate, includes measuring the thickness of the graphene layer directly grown on the silicon substrate, by using a ratio between a signal intensity of a photoelectron beam emitted from the graphene layer and a signal intensity of a photoelectron beam emitted from the silicon substrate.

## Claims

### Claim 1

A method of measuring a thickness of a graphene layer directly grown on a silicon substrate, by using an X-ray photoelectron spectroscopy (XPS) instrument, the method comprising:
emitting X-ray radiation toward the graphene layer directly grown on the silicon substrate using a source on the XPS instrument;
obtaining signal intensities from the graphene layer directly grown on the silicon substrate in response to emitting the X-ray radiation toward the graphene layer directly grown on the silicon substrate using a sensor on the XPS instrument; and
calculating the thickness tG of the graphene layer according to an equation below,
t
G
=
λ
E
⁢
A
⁢
L
⁢
cos
⁢
⁢
α
⁢
⁢
ln
⁢
⁢
(
R
exp
R
0
+
1
)
wherein
⁢
⁢
R
0
=
I
c
⁢
o
I
s
⁢
i
⁢
o
,
R
exp
=
I
C
I
s
⁢
i
,
λREAL is an effective attenuation length,
α is a detection angle for the XPS instrument,
Ico is a signal intensity of a photoelectron beam emitted from bulk-type graphene,
Isio is a signal intensity of a photoelectron beam emitted from bulk-type silicon,
Ic is a signal intensity of a photoelectron beam emitted from the graphene layer and obtained by the sensor on the XPS instrument in response to the graphene layer receiving X-ray radiation by the XPS instrument, and
Isi is a signal intensity of a photoelectron beam emitted from the silicon substrate and obtained by the sensor on the XPS instrument in response to the silicon substrate receiving X-ray radiation by the XPS instrument,
wherein R0 is obtained by a linear relationship between the signal intensity Isi of the photoelectron beam emitted from the silicon substrate and the signal intensity Ic of the photoelectron beam emitted from the graphene layer using the XPS instrument.

### Claim 2 (depends on 1)

The method of claim 1, wherein the graphene layer includes crystalline graphene or nanocrystalline graphene.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
obtaining the effective attenuation length via calibration, from a linear relationship between results of measurement by a transmission electron microscope and results of measurement by the XPS.

### Claim 4 (depends on 1)

The method of claim 1, wherein the bulk-type graphene has a thickness that is greater than or equal to about 10 nm.

### Claim 5

A method of measuring a thickness of a graphene layer directly grown on a silicon substrate such that an interface layer is formed between the silicon substrate and the graphene layer, by using an X-ray photoelectron spectroscopy (XPS) instrument, the method comprising:
emitting X-ray radiation toward the graphene layer directly grown on the silicon substrate using a source on the XPS instrument;
obtaining signal intensities from the graphene layer directly grown on the silicon substrate in response to emitting the X-ray radiation toward the graphene layer directly grown on the silicon substrate using a sensor on the XPS instrument; and
calculating the thickness tG of the graphene layer according to an equation below,
t
G
=
λ
E
⁢
A
⁢
L
⁢
⁢
cos
⁢
⁢
α
⁢
⁢
ln
(
I
C
R
0
K
+
I
s
⁢
i
+
⁢
1
)
wherein
⁢
⁢
R
0
=
I
c
⁢
o
I
s
⁢
i
⁢
o
,
λREAL is an effective attenuation length,
α is a detection angle for the XPS instrument,
Ico is a signal intensity of a photoelectron beam emitted from bulk-type graphene,
Isio is a signal intensity of a photoelectron beam emitted from bulk-type silicon,
Ic is a signal intensity of a photoelectron beam emitted from the graphene layer and obtained by the sensor on the XPS instrument in response to the graphene layer receiving X-ray radiation by the XPS instrument,
Isi is a signal intensity of a photoelectron beam emitted from the silicon substrate and obtained by the sensor on the XPS instrument in response to the silicon substrate receiving X-ray radiation by the XPS instrument, and K is a corrected value based on an effect of the interface layer, wherein
R0 is obtained by a linear relationship between the signal intensity Isi of the photoelectron beam emitted from the silicon substrate and the signal intensity Ic of the photoelectron beam emitted from the graphene layer using the XPS instrument.

### Claim 6 (depends on 5)

The method of claim 5, wherein the interface layer includes silicon carbide, silicon oxycarbide, and silicon oxide.

### Claim 7 (depends on 5)

The method of claim 5, wherein the graphene layer includes crystalline graphene or nanocrystalline graphene.

### Claim 8 (depends on 5)

The method of claim 5, further comprising:
obtaining the effective attenuation length via calibration, from a linear relationship between results of measurement by a transmission electron microscope and results of measurement by the XPS.