Abstract
We demonstrate the contact resistance reduction for III-V semiconductor-based electrical and optical devices using the interfacial dipole effect of ultrathin double interlayers in a metal-interlayers-semiconductor (M-I-S) structure. An M-I-S structure blocks metal-induced gap states (MIGS) to a sufficient degree to alleviate Fermi level pinning caused by MIGS, resulting in contact resistance reduction. In addition, the ZnO/TiO2 interlayers of an M-I-S structure induce an interfacial dipole effect that produces Schottky barrier height (ΦB) reduction, which reduces the specific contact resistivity (ρc) of the metal/n-type III-V semiconductor contact. As a result, the Ti/ZnO(0.5 nm)/TiO2(0.5 nm)/n-GaAs metal-double interlayers-semiconductor (M-DI-S) structure achieved a ρc of 2.51 × 10-5 Ω·cm2, which exhibited an ∼42 000× reduction and an ∼40× reduction compared to the Ti/n-GaAs metal-semiconductor (M-S) contact and the Ti/TiO2(0.5 nm)/n-GaAs M-I-S structure, respectively. The interfacial dipole at the ZnO/TiO2 interface was determined to be approximately −0.104 eV, which induced a decrease in the effective work function of Ti and, therefore, reduced ΦB. X-ray photoelectron spectroscopy analysis of the M-DI-S structure also confirmed the existence of the interfacial dipole. On the basis of these results, the M-DI-S structure offers a promising nonalloyed Ohmic contact scheme for the development of III-V semiconductor-based applications.
Original language | English |
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Pages (from-to) | 35614-35620 |
Number of pages | 7 |
Journal | ACS Applied Materials and Interfaces |
Volume | 8 |
Issue number | 51 |
DOIs | |
Publication status | Published - 2016 Dec 28 |
Keywords
- Fermi level pinning
- Schottky barrier
- gallium arsenide
- interfacial dipole
- specific contact resistivity
ASJC Scopus subject areas
- Materials Science(all)