Electron transport properties of InAs ultrathin films obtained by epitaxial lift-off and van der Waals bonding on flexible substrates

Abstract

We investigated InAs ultrathin films on flexible substrates. InAs layers grown on GaAs(001) are separated by epitaxial lift-off (ELO), followed by van der Waals bonding (VWB) on flexible substrates. We employed “normal” and “inverted” VWB; in the former, top and bottom sides are maintained during ELO and VWB, while inverted in the latter. From the InAs on flexible substrates, we fabricated Hall-bar devices with recess etch-thinning, using which electron transport properties depending on InAs layer thickness were characterized. For the inverted VWB, we observe very high electron mobilities of InAs ultrathin films, such as ∼10 000 cm2/V s for ∼100 nm thickness and ∼7000 cm2/V s for ∼20 nm. These carrier mobilities are highest not only for thin films on flexible substrates but also for InAs thin films; higher than those of InAs films grown on GaAs(111)A and membranes fabricated from them.

Minority carrier decay length extraction from scanning photocurrent profiles in two-dimensional carrier transport structures

“…For the case of n-type InAs thin film used in simulation, the typical drift–diffusion transport framework along with the Shockley–Read–Hall recombination model, Auger recombination model, and the constant mobility model was considered in the whole device structure including the source region. The material parameters are shown below: net doping 10 17 cm −3 , minority carrier lifetime 660 ps 6 , electron mobility 4000 cm 2 ·V −1 ·s −1 21 , hole mobility 60 cm 2 ·V −1 ·s −1 22 , and Auger coefficient of 2.2 × 10 −27 cm 6 ·s −1 23 . The bias of 0.01 V is set on the anode of the device, which corresponds to an applied electric field of 20 V·cm −1 .…”

Interface analysis of AlN/InAs(001) and AlN/Ge/InAs(001) by angle-resolved X-ray photoelectron spectroscopy

“…InAs is an important narrow-gap compound semiconductor with potential applications to ultra-high-speed electron devices. In particular, heterogeneous integration of InAs devices on foreign host substrates with low dielectric constants and high resistivities [1,2] has advantages for high-speed applications. Since InAs metal-insulatorsemiconductor field-effect transistors (MISFETs) are important devices for such applications, controlling of insulator-InAs interfaces, in particular for high-k insulators, is an important technological issue.…”

An InAs/high-k/low-k structure: Electron transport and interface analysis

“…[14][15][16][17] Nomarski optical microscope images of the Hall-bar devices are shown in the bottom of Fig. 1, where the differential interference contrasts indicate same smooth surfaces for the InAs/high-k/low-k and the InAs/low-k.…”

“…1. Using a heterostructure, InAs device layer (500 nm thickness)/ AlAs sacrificial layer (4 nm thickness)/ InAs buffer layer (2500 nm thickness)/ GaAs(001), we carried out ELO, [14][15][16][17] separation of the InAs device layer attached to an adhesive sheet. The InAs device layer was transferred onto an intermediate support, a sapphire(0001) coated by resists, followed by removal of the adhesive sheet and InAs surface cleaning using phosphoric acid.…”

“…8,9 In particular, heterogeneous integration of InAs devices on foreign host substrates is quite important. [10][11][12][13] We previously fabricated and investigated an InAs/low-k structure, where high-quality InAs thin films are bonded on host low-dielectric-constant (low-k) flexible substrates (FS), [14][15][16][17] by using epitaxial liftoff (ELO) and van der Waals bonding (VWB) method. 18,19 The InAs/low-k (InAs/FS) exhibits high electron mobilities, where the FS with k ∼ 3, polyethylene terephthalate (PET) coated by bisaziderubber, has a merit for device applications because of a low parasitic capacitance.…”