Interfacial band parameters of ultrathin ALD–Al2O3, ALD–HfO2, and PEALD–AlN/ALD–Al2O3 on c-plane, Ga-face GaN through XPS measurements

Abstract

Ultrathin oxides (UOs) and ultrathin nitrides (UNs) play a crucial role in forming lattice-mismatched semiconductor heterostructures that are fabricated by using semiconducting grafting approach. The grafting approach has shown its great potential to realize GaN-based heterojunction bipolar transistors by fulfilling the missing high-performance p-type nitrides with other p-type semiconductors. A handful of UO and UN dielectrics readily available by atomic layer deposition (ALD) satisfy the requirements of double-sided surface passivation and quantum tunneling for semiconductor grafting. Due to the states existing between the UO or UN conduction band and that of the GaN, the ALD deposited UO or UN layer can generate significant effects on the surface band-bending of GaN. Understanding the band parameters of the interface between UO or UN and c-plane Ga-face GaN can guide the selection of interfacial dielectrics for grafted GaN-based devices. In this study, we performed x-ray photoelectron spectroscopy measurements to obtain the band-bending properties on c-plane, Ga-face GaN samples coated by different ALD cycles of ultrathin-HfO2 or ultrathin AlN. The valence band spectra of GaN coated with ultrathin-ALD–Al2O3, ALD–HfO2, or PEALD–AlN/ALD–Al2O3 were further analyzed to calculate the valence and conduction band offsets between the ALD dielectrics and the Ga-face GaN under different thicknesses and post-deposition annealing conditions of the dielectrics.

Improved drain lag by reduced surface current in GaN HEMT via an ultrathin HfO2 blanket layer

“…Schottky leakage results display two orders of magnitude decrease. This reduction is owing to the large conduction band difference between HfO 2 and GaN [22]. As summarized in table 1, this improvement in the gate leakage is comparable to or even better than some of the reported work on thicker gate dielectrics.…”

“…Band diagram calculations were carried out in Silvaco ATLAS [21]. The band alignment parameters between HfO 2 and GaN were taken from the literature [22]. As shown in figure 2, HfO 2 deposition increases the barrier height for electrons and can effectively reduce the electron injection into the epitaxy.…”

Tunneling Electron-Mediated Electrochemical Activation of Peroxydisulfate for the Removal of Refractory Pollutants

“…In Figure S6, a broad and asymmetric O 1s peak is depicted, which is further deconvoluted into three peaks. The peak at 530.9 eV is attributed to Al–O bonds, the peak at 531.8 eV is associated with Al–OH hydroxyl groups resulting from H 2 O in ALD, and the peak at 532.9 eV could be related to CO. , As shown in Figure S7, the Si 2p core level spectrum comprises two distinct deconvolution peaks. The main peak is attributed to Si–Al bonding at 100.3 eV, while the other two peaks at 101.5 and 103.1 eV are attributed to Si–O bonding. , …”

Vertical Field-Plated NiO/Ga2O3 Heterojunction Power Diodes

“…the Si and the β-Ga2O3. The role of the interface SiGaOx has served the identical roles in other grafted heterostructures where an ultrathin Al2O3 layer was applied using atomic layer deposition (ALD) [45,[54][55][56][57][58][59][60][61]. surface conditions.…”