Valence and conduction band offsets at amorphous hexagonal boron nitride interfaces with silicon network dielectrics

摘要

To facilitate the design of heterostructure devices employing hexagonal/sp2 boron nitride, x-ray photoelectron spectroscopy has been utilized in conjunction with prior reflection electron energy loss spectroscopy measurements to determine the valence and conduction band offsets (VBOs and CBOs) present at interfaces formed between amorphous hydrogenated sp2 boron nitride (a-BN:H) and various low- and high-dielectric-constant (k) amorphous hydrogenated silicon network dielectric materials (a-SiX:H, X = O, N, C). For a-BN:H interfaces formed with wide-band-gap a-SiO2 and low-k a-SiOC:H materials (Eg ≅ 8.2−8.8 eV), a type I band alignment was observed where the a-BN:H band gap (Eg = 5.5 ± 0.2 eV) was bracketed by a relatively large VBO and CBO of ∼1.9 and 1.2 eV, respectively. Similarly, a type I alignment was observed between a-BN:H and high-k a-SiC:H where the a-SiC:H band gap (Eg = 2.6 ± 0.2 eV) was bracketed by a-BN:H with VBO and CBO of 1.0 ± 0.1 and 1.9 ± 0.2 eV, respectively. The addition of O or N to a-SiC:H was observed to decrease the VBO and increase the CBO with a-BN:H. For high-k a-SiN:H (Eg = 3.3 ± 0.2 eV) interfaces with a-BN:H, a slightly staggered type II band alignment was observed with VBO and CBO of 0.1 ± 0.1 and −2.3 ± 0.2 eV, respectively. The measured a-BN:H VBOs were found to be consistent with those deduced via application of the commutative and transitive rules to VBOs reported for a-BN:H, a-SiC:H, a-SiN:H, and a-SiO2 interfaces with Si (100).