Extremely low nonalloyed and alloyed contact resistance using an InAs cap layer on InGaAs by molecular-beam epitaxy

Abstract

Extremely low alloyed and nonalloyed ohmic contact resistances have been formed on n-type InAs/In0.53Ga0.47As/In0.52Al0.48As structures grown on InP(Fe) by molecular-beam epitaxy. To insure the accuracy of the small contact resistances measured, an extended transmission line model was used to extrapolate contact resistances from test patterns with multiple gap spacings varying from 1 to 20 μm. For a 150-Å-thick InAs layer doped to 2×1018 cm−3 and a 0.1-μm-thick InGaAs layer doped to 1×1018 cm−3, a specific contact resistance of 2.6×10−8 Ω* cm2 was measured for the nonalloyed contact, while a resistance less than 1.7×10−8 Ω* cm2 is reported for the alloyed contact. Conventional Au-Ge/Ni/Au was used for the ohmic metal contact and alloying was performed at 500 °C for 50 s in flowing H2. Using a thermionic field emission model, the barrier height at the InAs/InGaAs interface was calculated to be 20 meV.

$\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$ Channel MOSFETs With Self-Aligned InAs Source/Drain Formed by MEE Regrowth

“…This sheet resistance is comparable to that of the latticematched n + In 0.53 Ga 0.47 As regrowths reported earlier [10]. The n ++ InAs/n ++ InGaAs interface resistance is observed to be less than 2.0 Ω · μm 2 [14]. The log(I D )−V GS characteristics on 200-nm L g MOSFETs (Fig.…”

Near-ideal electrical properties of InAs/WSe2 van der Waals heterojunction diodes

“…Low resistance metal contacts are readily formed to InAs as previously reported due to its low conduction band edge. 25 On the other hand, it is hard to form ohmic metal contacts with WSe 2 due to its large bandgap. Previous studies by our group have shown that the Schottky barrier to WSe 2 can be significantly thinned by NO 2 doping, 24 thereby enabling formation of low resistance contacts for hole injection.…”

“…Ohmic contacts were assumed for the InAs/Pd and WSe 2 /Pd junctions. 24,25 The forward current was fit with a series FIG. 3.…”

STM and TS Study of InAs Quantum Dots Immobilized on Au and Pt Surfaces

“…InAs is different from most III−V semiconductors in that the Fermi level of common metals is pinned above its conduction band (CB) edge . As a consequence of this, in addition to its relatively narrow band gap (0.36 eV), and its large electron and hole mobilities (33 000 and 460 cm 2 V -1 s -1 , respectively), InAs forms low resistance contacts to metals. − The interaction between Q-InAs and metals (viz., the STM tip or the underlying metal) is, however, fundamentally different from that of bulk InAs, because of the absence of a band structure in the QDs and their similarity to molecules, albeit very large; in addition to their wider HOMO−LUMO separation.…”