Aluminum oxide as passivation and gate insulator in GaAs-based field-effect transistors prepared in situ by metal-organic vapor deposition

Abstract

Application of GaAs-based metal-oxide-semiconductor (MOS) structures, as a “high carrier mobility” alternative to conventional Si MOS transistors, is still hindered due to difficulties in their preparation with low surface/interface defect states. Here, aluminum oxide as a passivation and gate insulator was formed by room temperature oxidation of a thin Al layer prepared in situ by metal-organic chemical vapor deposition. The GaAs-based MOS structures yielded two-times higher sheet charge density and saturation drain current, i.e., up to 4 × 1012 cm−2 and 480 mA/mm, respectively, than the counterparts without an oxide surface layer. The highest electron mobility in transistor channel was found to be 6050 cm2/V s. Capacitance measurements, performed in the range from 1 kHz to 1 MHz, showed their negligible frequency dispersion. All these results indicate an efficient suppression of the defect states by in situ preparation of the semiconductor structure and aluminum oxide used as a passivation and gate insulator.

Improved interfacial and electrical properties of GaAs metal-oxide-semiconductor capacitors with HfTiON as gate dielectric and TaON as passivation interlayer

“…GaAs-based metal-oxide-semiconductor field-effect transistor (MOSFET) with high-k gate dielectric has received significant efforts in the past decades due to its higher carrier mobility, larger energy bandgap, and lower power consumption than those of its Si counterpart. 1,2 However, direct deposition of high-k dielectric on GaAs yields poor electrical characteristics due to easy formation of native oxide on the GaAs surface which results in an extremely high density of interface states, thus inducing Fermi-level pinning at the GaAs/high-k interface. 3 So, different surface-passivation techniques of GaAs have been intensively studied.…”

High-performance GaAs metal-oxide-semiconductor capacitor by using NbAlON as high-k gate dielectric

“…In order to counteract the increasing degradation caused by Si-based metal-oxide-semiconductor (MOS) technology approaching its scaling limit and fulfill the requirements of higher performance and lower power consumption in the future, GaAs has received significant attention recently due to its higher electron mobility, larger bandgap, and higher breakdown field than those of Si. [1][2][3] For GaAs MOS devices, ideal gate dielectrics should possess (i) high dielectric constant (high-k), (ii) sufficient bandgap and band offset with the conduction band of GaAs, and (iii) thermal stability and low interface-state density (D it ) with GaAs. 4 Many high-k materials (e.g., HfO 2 , 5 La 2 O 3 , 6 Y 2 O 3 , 7 and ZrO 2 (Ref.…”

Passivation of oxide traps in gallium arsenide (semiconductor) metal-oxide-semiconductor capacitor with high-k dielectric by using fluorine incorporation

“…1 Much attention has been paid to exploring new materials capable of providing high drive current, with III-V compound semiconductor as one of the most promising materials to replace Si. 2,3 Gallium arsenide (semiconductor) (GaAs) metal-oxide-semiconductor (MOS) device with high-k (dielectric constant) gate dielectric has received significant efforts due to its larger bandgap and higher electron mobility than its Si counterpart. 4,5 Among the available high-k materials, TaHfO has been demonstrated to exhibit excellent electrical properties such as relatively high k value, peak electron mobility and crystallization temperature.…”