title: Top-down, in-plane GaAs nanowire MOSFETs on an Al2O3 buffer with a trigate oxide from focused ion-beam milling and chemical oxidation.
abstract: The top-down fabrication of an in-plane nanowire (NW) GaAs metal-oxide-semiconductor field-effect transistor (MOSFET) with a trigate oxide implemented by liquid-phase chemical-enhanced oxidation (LPCEO) is reported. A 2 μm long channel having an effective cross section ∼70 × 220 nm(2) is directly fabricated into an epitaxial n (+)-GaAs layer. This in-plane NW structure is achieved by focused ion beam (FIB) milling and hydrolyzation oxidation resulting in electronic isolation from the substrate through a semiconductor-on-insulator structure with an n (+)-GaAs/Al2O3 layer stack. The channel is epitaxially connected to the μm-scale source and drain within a single layer for a planar MOSFET to avoid any issues of ohmic contact and LPCEO to the NW. To fabricate a MOSFET, the top and the two sidewalls of the in-plane NW are oxidized by LPCEO to relieve the surface damage from FIB as well as to transform these surfaces to a ∼15 nm thick gate oxide. This trigate device has threshold voltage ∼0.14 V and peak transconductance ∼35 μS μm(-1) with a subthreshold swing ∼150 mV/decade and on/off ratio of drain current ∼10(3), comparable to the performance of bottom-up NW devices.
authors: Center for High Technology Materials and Department of Electrical and Computer Engineering, University of New Mexico, 1313 Goddard SE, Albuquerque, NM 87106, USA.
authors: S C
authors: SC
authors: Lee
authors: A
authors: A
authors: Neumann
authors: Y-B
authors: YB
authors: Jiang
authors: K
authors: K
authors: Artyushkova
authors: S R J
authors: SR
authors: Brueck