Epitaxy of Single‐Crystalline GaN Film on CMOS‐Compatible Si(100) Substrate Buffered by Graphene

Abstract

Fabricating single-crystalline gallium nitride (GaN)-based devices on a Si(100) substrate, which is compatible with the mainstream complementary metal-oxide-semiconductor circuits, is a prerequisite for next-generation high-performance electronics and optoelectronics. However, the direct epitaxy of single-crystalline GaN on a Si(100) substrate remains challenging due to the asymmetric surface domains of Si(100), which can lead to polycrystalline GaN with a two-domain structure. Here, by utilizing singlecrystalline graphene as a buffer layer, the epitaxy of a single-crystalline GaN film on a Si(100) substrate is demonstrated. The in situ treatment of graphene with NH 3 can generate sp 3 CN bonds, which then triggers the nucleation of nitrides. The one-atom-thick single-crystalline graphene provides an in-plane driving force to align all GaN domains to form a single crystal. The nucleation mechanisms and domain evolutions are further clarified by surface science exploration and first-principle calculations. This work lays the foundation for the integration of GaN-based devices into Si-based integrated circuits and also broadens the choice for the epitaxy of nitrides on unconventional amorphous or flexible substrates.

The stability of graphene and boron nitride for III-nitride epitaxy and post-growth exfoliation

“…In general, the N 1s of N-doped graphene is characterized by three peak positions, these are, pyridinic-N (398-399 eV), pyrrolic-N (400-401 eV), and graphitic-N (401-402 eV). 7,16,[37][38][39][40][41][42][43][44][45]47 Recently, Chen et al demonstrated a AlN/graphene/sapphire structure using N-doped graphene. 48 They observed N-doped graphene with AlN and showed sp 2 C-N, and Al-N bonds in the N 1s scan using XPS, although N-doped graphene was covered by AlN.…”

“…The epitaxy caused by a 2-D material, termed van der Waals epitaxy (vdWE), reduces the dislocation density of the grown material, which strongly affects the device properties, and also allows exfoliation of the grown material from the substrate owing to the weak chemical bond. [1][2][3][4] The advantages of vdWE have been conrmed using various structures, such as gallium nitride (GaN) or aluminium nitride (AlN) growth on graphene/silicon carbide (SiC), 5 graphene/ silicon dioxide (SiO 2 ), [6][7][8][9] graphene/silicon (Si), [10][11][12] graphene/ sapphire (Al 2 O 3 ), [13][14][15][16][17][18] and hexagonal boron nitride (h-BN)/ Al 2 O 3 . 19,20 However, the remaining dislocation density on vdWE is still a hurdle to achieving high-quality semiconductors.…”

“…13,16 Feng et al have successfully created a GaN/graphene/ SiO 2 structure using ambient NH 3 annealing on graphene. 7 Chen et al have also shown UV-LED growth on graphene/Al 2 O 3 using N 2 plasma treatment before growth. 16 These results conrm that N-doped graphene on a substrate containing an oxygen (O) atom is a promising approach to enabling vdWE.…”

Graphene‐Assisted Epitaxy of Nitrogen Lattice Polarity GaN Films on Non‐Polar Sapphire Substrates for Green Light Emitting Diodes

“…There is no dangling bond for N atom in sp 2 ‐like CN bond, while there is one dangling bond left for each N atom in sp 3 ‐like CN bonds, as reported previously. [ 9,17,38 ] Therefore, when the Ga and N adatoms are supplied, Ga adatom will connect with this dangling bond to form CNGa bond and thus initiate the growth. XPS study of 5‐nm‐thick GaN deposited on the graphene/Al 2 O 3 at 780 °C also confirms this.…”

Van der Waals Epitaxy of III-Nitrides and Its Applications

“…The related research work of 2D GaN and van der Waals solids also lights the way for III-nitride-based novel devices fabrication. However, some obstacles, including large-scale single-crystalline epilayer preparation (2-in wafer-scale GaN van der Waals epilayer is available now [ 65 ]), uniformity of epilayer doping, and contact resistance reduction of the device still need to overcome.…”