The distinguished properties of hexagonal boron nitride ( h-BN), specifically its atomically smooth surface, large critical electric field, and large electronic bandgap, make it ideal for thin film microelectronics and as an ultrawide bandgap semiconductor. Owing to weak van der Waals interactions between layers, h-BN exhibits a significant degree of anisotropic thermal conductivity. The in-plane thermal conductivity of h-BN has extensively been studied, yet the only measured data of cross-plane thermal conductivity ( k ) are for exfoliated h-BN films. Exfoliation from bulk crystals is not a sustainable method for scalable production of h-BN due to its low repeatability, low yield, poor control of sample thickness, and limitation to small areas. Thus, it is necessary to investigate the thickness-dependence of k for thin films grown by a practical growth method, such as pulsed laser deposition (PLD), which enables the production of reliable and large-area h-BN films with a control of film thickness. We grew h-BN using PLD at 750 °C and observed a decreasing trend of k as thickness increases from 30 to 300 nm, varying from ∼1.5 to ∼0.2 W/(m K). We observed a relatively high k value for h-BN at a thickness of 30 nm, providing insight into the k of PLD-grown films suitable for electronics applications.

1.
I.
Ferain
,
C. A.
Colinge
, and
J. P.
Colinge
, “
Multigate transistors as the future of classical metal–oxide–semiconductor field-effect transistors
,”
Nature
479
(
7373
),
310
316
(
2011
).
2.
A.
Balandin
, “
Chill out
,”
IEEE Spectrum
46
(
10
),
34
39
(
2009
).
3.
S. V.
Garimella
,
A. S.
Fleischer
,
J. Y.
Murthy
,
A.
Keshavarzi
,
R.
Prasher
,
C.
Patel
,
S. H.
Bhavnani
,
R.
Venkatasubramanian
,
R.
Mahajan
,
Y.
Joshi
,
B.
Sammakia
,
B. A.
Myers
,
L.
Chorosinski
,
M.
Baelmans
,
P.
Sathyamurthy
, and
P. E.
Raad
, “
Thermal challenges in next-generation electronic systems
,”
IEEE Trans. Comp. Packag. Technol.
31
(
4
),
801
815
(
2008
).
4.
E.
Pop
and
K. E.
Goodson
, “
Thermal phenomena in nanoscale transistors
,”
J. Electron. Packag.
128
(
2
),
102
108
(
2006
).
5.
A. L.
Moore
and
L.
Shi
, “
Emerging challenges and materials for thermal management of electronics
,”
Materials
17
(
4
),
163
174
(
2014
).
6.
E.
Pop
,
S.
Sinha
, and
K. E.
Goodson
, “
Heat generation and transport in nanometer-scale transistors
,”
Proc. IEEE
94
(
8
),
1587
1601
(
2006
).
7.
R.
Warzoha
,
A.
Wilson
,
B.
Donovan
,
N.
Donmezer
,
A.
Giri
,
P.
Hopkins
,
S.
Choi
,
D.
Pahinkar
,
J.
Shi
,
S.
Graham
,
Z.
Tian
, and
L.
Ruppalt
, “
Applications and impacts of nanoscale thermal transport in electronics packaging
,”
J. Electron. Packag.
143
,
020804
(
2020
).
8.
N.
Alem
,
R.
Erni
,
C.
Kisielowski
,
M. D.
Rossell
,
W.
Gannett
, and
A.
Zettl
, “
Atomically thin hexagonal boron nitride probed by ultrahigh-resolution transmission electron microscopy
,”
Phys. Rev. B
80
,
155425
(
2009
).
9.
P.
Jiang
,
X.
Qian
,
R.
Yang
, and
L.
Lindsay
, “
Anisotropic thermal transport in bulk hexagonal boron nitride
,”
Phys. Rev. Mater.
2
(
6
),
064005
(
2018
).
10.
Z.
Lin
,
C.
Liu
, and
Y.
Chai
, “
High thermally conductive and electrically insulating 2D boron nitride nanosheet for efficient heat dissipation of high-power transistors
,”
2D Mater.
3
(
4
),
041009
(
2016
).
11.
J. C.
Zheng
,
L.
Zhang
,
A. V.
Kretinin
,
S. V.
Morozov
,
Y. B.
Wang
,
T.
Wang
,
X.
Li
,
F.
Ren
,
J.
Zhang
,
C. Y.
Lu
,
J. C.
Chen
,
M.
Lu
,
H. Q.
Wang
,
A. K.
Geim
, and
K. S.
Novoselov
, “
High thermal conductivity of hexagonal boron nitride laminates
,”
2D Mater.
3
(
1
),
011004
(
2016
).
12.
M. J.
Meziani
,
W. L.
Song
,
P.
Wang
,
F.
Lu
,
Z.
Hou
,
A.
Anderson
,
H.
Maimaiti
, and
Y. P.
Sun
, “
Boron nitride nanomaterials for thermal management applications
,”
ChemPhysChem
16
(
7
),
1339
1346
(
2015
).
13.
L.
Fu
,
T.
Wang
,
J.
Yu
,
W.
Dai
,
H.
Sun
,
Z.
Liu
,
R.
Sun
,
N.
Jiang
,
A.
Yu
, and
C.-T.
in
, “
An ultrathin high-performance heat spreader fabricated with hydroxylated boron nitride nanosheets
,”
2D Mater.
4
(
2
),
025047
(
2017
).
14.
E. K.
Sichel
,
R. E.
Miller
,
M. S.
Abrahams
, and
C. J.
Buiocchi
, “
Heat capacity and thermal conductivity of hexagonal pyrolytic boron nitride
,”
Phys. Rev. B
13
(
10
),
4607
4611
(
1976
).
15.
G.
Cassabois
,
P.
Valvin
, and
B.
Gil
, “
Hexagonal boron nitride is an indirect bandgap semiconductor
,”
Nature Photon.
10
,
262
266
(
2016
).
16.
C.
Wang
,
J.
Guo
,
L.
Dong
,
A.
Aiyiti
,
X.
Xu
, and
B.
Li
, “Superior thermal conductivity in suspended bilayer hexagonal boron nitride,”
Scientific Reports
6
,
25334
(
2016
).
17.
G. R.
Jaffe
,
K. J.
Smith
,
K.
Watanabe
,
T.
Taniguchi
,
M. G.
Lagally
,
M. A.
Eriksson
, and
V. W.
Brar
, “
Long phonon mean free paths observed in cross-plane thermal-conductivity measurements of exfoliated hexagonal boron nitride
,” arXiv:2103.07452 (
2021
).
18.
S.
Saha
,
A.
Rice
,
A.
Ghosh
,
S. M. N.
Hasan
,
W.
You
,
T.
Ma
,
A.
Hunter
,
L. J.
Bissell
,
R.
Bedford
,
M.
Crawford
, and
S.
Arafin
, “
Comprehensive characterization and analysis of hexagonal boron nitride on sapphire
,”
AIP Adv.
11
,
55008
(
2021
).
19.
T.
Shen
,
S.
Liu
,
W.
Yan
, and
J.
Wang
, “
Highly efficient preparation of hexagonal boron nitride by direct microwave heating for dye removal
,”
J. Mater. Sci.
54
,
8852
8859
(
2019
).
20.
G.
Wang
,
J.
Chen
,
J.
Meng
,
Z.
Yin
,
J.
Jiang
,
Y.
Tian
,
J.
Li
,
J.
Wu
,
P.
Jin
, and
X.
Zhang
, “
Direct growth of hexagonal boron nitride films on dielectric sapphire substrates by pulsed laser deposition for optoelectronic applications
,”
Fundam. Res.
1
,
677
683
(
2021
).
21.
P.
Widmayer
,
H.-G.
Boyen
,
P.
Ziemann
,
P.
Reinke
, and
P.
Oelhafen
, “
Electron spectroscopy on boron nitride thin films: Comparison of near-surface to bulk electronic properties
,”
Phys. Rev. B
59
(
7
),
5233
5241
(
1999
).
22.
C.
Zhi
,
S.
Ueda
, and
H.
Zeng
, “
Weak morphology dependent valence band structure of boron nitride
,”
J. Appl. Phys.
114
,
54306
(
2013
).
23.
R.
Singh
,
G.
Kalita
,
R. D.
Mahyavanshi
,
S.
Adhikari
,
H.
Uchida
,
M.
Tanemura
,
M.
Umeno
, and
T.
Kawahara
, “
Low temperature wafer-scale synthesis of hexagonal boron nitride by microwave assisted surface wave plasma chemical vapour deposition
,”
AIP Adv.
9
,
035043
(
2019
).
24.
K. T.
Regner
,
S.
Majumdar
, and
J. A.
Malen
, “
Instrumentation of broadband frequency domain thermoreflectance for measuring thermal conductivity accumulation functions
,”
Rev. Sci. Instrum.
84
(
6
),
064901
(
2013
).
25.
A. J.
Schmidt
,
R.
Cheaito
, and
M.
Chiesa
, “
A frequency-domain thermoreflectance method for the characterization of thermal properties
,”
Rev. Sci. Instrum.
80
,
94901
(
2009
).
26.
J.
Yang
, “
Thermal property measurement with frequency domain thermoreflectance
,” Ph.D. dissertation (
Boston University College of Engineering
,
2016
).
27.
C. C.
Chen
,
Z.
Li
,
L.
Shi
, and
S. B.
Cronin
, “
Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction
,”
Appl. Phys. Lett.
104
(
8
),
081908
(
2014
).
28.
Z.
Yan
,
L.
Chen
,
M.
Yoon
, and
S.
Kumar
, “
Phonon transport at the interfaces of vertically stacked graphene and hexagonal boron nitride heterostructures
,”
Nanoscale
8
(
7
),
4037
4046
(
2016
).
29.
M. S.
Islam
,
I.
Mia
,
S.
Ahammed
,
C.
Stampfl
, and
J.
Park
, “
Exceptional in-plane and interfacial thermal transport in graphene/2D-SiC van der Waals heterostructures
,”
Sci. Rep.
10
(
1
),
22050
(
2020
).
30.
Z.
Ding
,
Q. X.
Pei
,
J. W.
Jiang
,
W.
Huang
, and
Y. W.
Zhang
, “
Interfacial thermal conductance in graphene/MoS2 heterostructures
,”
Carbon N. Y.
96
,
888
896
(
2016
).
31.
B.
Liu
,
J. A.
Baimova
,
C. D.
Reddy
,
A. W. K.
Law
,
S. V.
Dmitriev
,
H.
Wu
, and
K.
Zhou
, “
Interfacial thermal conductance of a silicene/graphene bilayer heterostructure and the effect of hydrogenation
,”
ACS Appl. Mater. Interfaces
6
(
20
),
18180
18188
(
2014
).
32.
Y.
Wang
,
L.
Xu
,
Z.
Yang
,
H.
Xie
,
P.
Jiang
,
J.
Dai
,
W.
Luo
,
Y.
Yao
,
E.
Hitz
,
R.
Yang
,
B.
Yang
, and
L.
Hu
, “
High temperature thermal management with boron nitride nanosheets
,”
Nanoscale
10
(
1
),
167
173
(
2018
).
33.
J. R.
Prekodravac
,
D. P.
Kepić
,
K.
Kepić
,
J. C.
Colmenares
,
D. A.
Giannakoudakis
, and
S. P. J.
Jovanović
, “
A comprehensive review on selected graphene synthesis methods: From electrochemical exfoliation through rapid thermal annealing towards biomass pyrolysis
,”
J. Mater. Chem. C
9
,
6722
(
2021
).
34.
L.
Liu
and
X.
Chen
, “
Effect of surface roughness on thermal conductivity of silicon nanowires
,”
J. Appl. Phys.
107
(
3
),
033501
(
2010
).
35.
J.
Wang
,
X.
Mu
,
X.
Wang
,
N.
Wang
,
F.
Ma
,
W.
Liang
, and
M.
Sun
, “
The thermal and thermoelectric properties of in-plane C-BN hybrid structures and graphene/h-BN van der Waals heterostructures
,”
Mater. Today Phys.
5
,
29
57
(
2018
).
36.
G.
Alvarez-Escalante
et al, “
High thermal conductivity and ultrahigh thermal boundary conductance of homoepitaxial AlN thin films
,”
APL Mater.
10
,
011115
(
2022
).

Supplementary Material

You do not currently have access to this content.