Effects of Initial Surface Reconstruction on Silicon Interface Control Layer Based Passivation of (001) GaAs Surfaces Studied in an Ultrahigh-Vacuum Multichamber System

Abstract

In order to understand and to further optimize the silicon interface control layer (Si ICL)-based passivation process for GaAs, the effects of the initial surface reconstruction of GaAs on the microscopic surface structures of the Si ICL and on the macroscopic electronic properties are studied in situ, using an ultrahigh-vacuum (UHV) multi-chamber system. (2×4) and c(4×4) GaAs surfaces were prepared by molecular beam epitaxy (MBE). Surface structures and compositions were studied by UHV scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Macroscopic electronic properties of the passivated surfaces were investigated by XPS band bending measurements, UHV contactless capacitance-voltage (C-V) measurements and UHV photoluminescence (PL) methods. The Si layer grown on the initially reconstructed c(4×4) surface was found to be more ordered and flatter than that grown on the initially reconstructed (2×4) surface. This difference showed a strong correlation with the macroscopic electronic properties after the Si ICL-based passivation process measured by XPS, UHV contactless C-V and PL techniques. The results indicate the importance of the two-dimensional order on the Si-deposited surfaces for successful passivation.

Formation of ultrathin SiNx∕Si interface control double layer on (001) and (111) GaAs surfaces for ex situ deposition of high-k dielectrics

“…Thus, the best known and the most traditional As-rich ͑2 ϫ 4͒ surface seems to be actually the most difficult one to control, most probably due to complex missing dimer reconstruction structure and volatile nature of As atoms in agreement with our previous result 27 and also with a more detailed study by Chambers and Loebs. 28 As for the observed band bending change, it was previously argued 28,29 that it is not due to surface state removal but due to compensation of negative surface state charge by positive charge of As donors incorporated in the Si layer.…”

MBE growth and in situ XPS characterization of silicon interlayers on (111)B surfaces for passivation of GaAs quantum wire devices

“…On the other hand, large shifts of E FS by 250-420 meV toward E C took place after Si-ICL growth on all of the (111) GaAs, band bending stayed nearly the same or became even slightly worse by Si-ICL growth in agreement with our previous result [9] and also with a more detailed study by Chambers and Loebs [10].…”

Effects of gap states on scanning tunneling spectra observed on (110)- and (001)-oriented clean surfaces and ultrathin Si layer covered surfaces of GaAs prepared by molecular beam epitaxy

“…11,14 Briefly, submonolayer Si deposition on the initially ͑2ϫ4͒ reconstructed ͑001͒ GaAs surface produced three regions, namely, the region maintaining the initial ͑2ϫ4͒ reconstructed structure, the region where the initial missing-dimer trench was filled with Si atoms, and the hole region where initial As dimers were removed and underlying Ga atoms appeared. Further Si deposition produced Si terrace regions.…”