Unpinned gallium oxide/GaAs interface by hydrogen and nitrogen surface plasma treatment

Abstract

The Fermi level at the Ga oxide/GaAs interface has been unpinned by rf plasma cleaning the GaAs surface in H2 and N2. Following plasma cleaning, a Ga oxide film is reactively electron beam deposited onto the substrate. Metal-oxide-semiconductor (MOS) capacitors fabricated on these structures show good high-frequency capacitance-voltage characteristics. This indicates that the density of interface states has been reduced to ∼1011 eV−1 cm−2. The MOS capacitors are found to be stable in air after several months.

Influence of plasma-based in-situ surface cleaning procedures on HfO2/In0.53Ga0.47As gate stack properties

“…To reduce the large trap densities at interfaces between In 0.53 Ga 0.47 As and the gate dielectric (typically Al 2 O 3 or HfO 2 ), various surface preparation and passivation methods are currently being investigated. [1][2][3][4][5][6][7][8][9] Interface trap densities (D it ), at least around midgap, are relatively straight-forward to detect for In 0.53 Ga 0.47 As, because of its narrow band gap (0.75 eV (Ref. 10)); they cause, for example, a frequency-dependent hump in the depletion region of capacitance-voltage (CV) characteristics, 11,12 and peaks in normalized conductance maps.…”

Growth and characterization of gallium oxide thin films by radiofrequency magnetron sputtering

“…The most suitable structure for applications is the monoclinic β-Ga 2 O 3 phase (a = 1.221 nm, b = 0.304 nm, c = 0.580 nm and β = 103.8°, space group: C2/m) which appears to be extremely stable chemically and thermally (melting point at 1800 °C) and may be an alternative choice to other transparent conductive oxide (TCO) materials (sulphide-based phosphors) usually dedicated to optoelectronic devices. Various growth techniques have been used to prepare thin films of this material: electron beam evaporation [8], spray pyrolysis deposition [9], sol gel process [7] and radiofrequency (RF) magnetron sputtering [10].…”

Detection of Ga suboxides and their impact on III-V passivation and Fermi-level pinning

“…Despite having been studied in great detail for more than 35 years, this interface and the identification of the bonding configurations that cause the defects has remained challenging. [1][2][3][4] Problems with metaloxide-semiconductor ͑MOS͒ devices on GaAs and InGaAs, including frequency dispersion of capacitance and suboptimal electron mobility, have been attributed to a number of different surface species including Ga-O bonds, As-O bonds, elemental As, and As and Ga antisites. 5 Recent studies have shown that Ga-O ͑Ref.…”

“…Possible identities for this oxidation state ͑which was not studied here͒ include Ga͑AsO 3 ͒ 3 ͑Ref. 12͒ as well as Ga͑OH͒ 3 . This state is removed easily with chemical treatment.…”