Growth Temperature Effects of Chemical Vapor Deposition‐Grown Boron Nitride Layer Using B₂H₆ and NH₃

Abstract

The boron nitride (BN) thin films on Al2O3 substrates grown by chemical vapor deposition (CVD) using alternating supply of B2H6 and NH3 are investigated. A significant reduction in growth rates is observed when the growth temperature (Tg) is decreased from 1360 to 1140 °C, indicating incomplete decomposition of B2H6. The 2θ/ω scans of high‐resolution X‐ray diffraction (HRXRD) reveal that the intensity ratio of 2θ = 26.7°/54.0° is 16, which is close to the theoretical intensity ratio for hexagonal BN (h‐BN) of 17. By reducing Tg, the peak at 2θ = 26.2° is appeared, which is considered to the turbostratic BN (t‐BN). The Raman shift at 1369 cm−1 with a full width at half maximum of 20 cm−1 is analyzed, corresponding to the first‐order E2g symmetry vibrational mode in h‐BN. The high‐resolution transmission electron microscopy (HRTEM) confirms aligned 2D stacking of BN layers and the distance between interlayers of 0.3326 nm. The interlayers of 1.0 nm AlON are identified between BN layers and Al2O3 substrate.

Comparative Study of Boron Precursors for Chemical Vapor‐Phase Deposition‐Grown Hexagonal Boron Nitride Thin Films

“…During this period, there was no BN growth, but a thin AlON layer (≈1 nm) was formed under NH 3 exposure. [ 7 ]…”

“…[ 35 ] As a result, the induced compressive strain in the BN layer was released when the wafer cooled down from T g to RT. The size and height of the wrinkles strongly depend on the film thickness, [ 7 ] which is, in turn, related to the compressive strain in the BN layer. The size and height of the wrinkles obtained using TMB are slightly larger than those obtained using B 2 H 6 .…”

“…Thus, wafer‐scale mass production is expected to be realized through hetero‐epitaxy of BN thin films grown on foreign substrates. There are several growth methods for growing BN films, such as thermal chemical vapor‐phase deposition (CVD), [ 4–27 ] plasma‐assisted CVD, [ 28–31 ] and molecular beam epitaxy (MBE). [ 32 ] BN films have been demonstrated on various substrates, including sapphire, [ 4–7,9–26 ] Cu, [ 8 ] Ni, [ 21,27,28 ] SiC, [ 24,26 ] GaN, [ 29 ] Si, [ 30,31,33 ] and highly‐oriented pyrolytic graphite.…”

“…There are several growth methods for growing BN films, such as thermal chemical vapor‐phase deposition (CVD), [ 4–27 ] plasma‐assisted CVD, [ 28–31 ] and molecular beam epitaxy (MBE). [ 32 ] BN films have been demonstrated on various substrates, including sapphire, [ 4–7,9–26 ] Cu, [ 8 ] Ni, [ 21,27,28 ] SiC, [ 24,26 ] GaN, [ 29 ] Si, [ 30,31,33 ] and highly‐oriented pyrolytic graphite. [ 32 ] The boron precursors include borazine (B 3 N 3 H 6 ), [ 8 ] boron halides (BF 3 , BCl 3 , and BBr 3 ), [ 9,27,28 ] triethyl boron ((C 2 H 5 ) 3 B, TEB), [ 4,5,10–23 ] trimethyl boron ((CH 3 ) 3 B, TMB), [ 24,25 ] and diborane (B 2 H 6 ).…”

“…[ 32 ] The boron precursors include borazine (B 3 N 3 H 6 ), [ 8 ] boron halides (BF 3 , BCl 3 , and BBr 3 ), [ 9,27,28 ] triethyl boron ((C 2 H 5 ) 3 B, TEB), [ 4,5,10–23 ] trimethyl boron ((CH 3 ) 3 B, TMB), [ 24,25 ] and diborane (B 2 H 6 ). [ 6,7,26,27,30,31,33 ]…”