Open AccessApplication of GeTe phase-change films in the directly heated two-port switch design
Author(s) -
Sanyin Qu,
J. H. Zhang,
Lina Gao,
H. W. Chen,
X. Li,
J. M. Wang
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/770/1/012028
Subject(s) - materials science , amorphous solid , raman spectroscopy , annealing (glass) , crystallization , poling , electrical resistivity and conductivity , phase (matter) , crystallography , optoelectronics , analytical chemistry (journal) , optics , electrical engineering , composite material , chemistry , ferroelectricity , physics , organic chemistry , chromatography , dielectric , engineering
Phase-change (PC) materials offer the property of thermally induced reversible change and exhibit different resistance values due to the structure changes between crystalline and amorphous phases. In this work, GeTe films with a thickness of 100 nm were deposited on the glass substrates by radio-frequency magnetron sputtering and annealed at different temperatures. The XRD analysis showed diffraction peaks corresponding to the rhombohedral structure of c-GeTe (021), (200), (202), and (220), respectively. Upon annealing at 300 and 340°C, the rhombohedral structure would transform into a rock salt structure. The Raman analysis revealed that a-Ge-Te covalent bond is the mixed structure of tetrahedron and defective octahedron changing into tetrahedral cells. The resistivity declined sharply from 0.72 to 3.8× 10 −6 Ω-m, whereas the Hall mobility of holes sharply rose to 300 m 2 /Vs. Based on the above films, a two-port directly heated switch device was designed and fabricated in sandwich structure to verify its phase-change characteristics. Low-resistance state was converted from crystallization with a 20ns 9V voltage pulse, while high-resistance state was by passing a 2 μs 2V voltage pulse. The on/off resistance ratio of switch could reach five orders of magnitude, while the switch state remained stable after the process termination. The results obtained strongly suggest that GeTe is a promising material for RF switches.