Changes in morphology and local conductance of GeTe-Sb sub(2) Te sub(3) superlattice films on silicon observed by scanning probe microscopy in a lithography mode

• Published in: Japanese Journal of Applied Physics Vol. 55; no. 4
• Main Authors: Bolotov, Leonid, Tada, Tetsuya, Saito, Yuta, Tominaga, Junji
• Format: Journal Article
• Language: English
• Published: 01.04.2016
• Subjects: Conductance; Electric potential; Lithography; Morphology; Scanning probe microscopy; Superlattices; Switching; Voltage
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.55.04EK02

Changes in the morphology and conductance state of [(GeTe) sub(2)(Sb sub(2) Te sub(3))] superlattice (SL) films on Si(100) caused by external voltage were investigated by multimode scanning probe microscopy (MSPM) and scanning probe lithography (SPL) at room temperature in vacuum. After SPL patterning at a write voltage exceeding a threshold value, grain-dependent changes in transverse film conductance appeared in the MSPM current maps at a low voltage. Specific details of the conductance state switching were dependent on the film growth process. In uniform films grown in a two-step process, a threshold voltage of 1.6 V and a minimum switching power of ~15 pW were obtained for conductance switching activated by high-energy electrons injected from the probe. Above 3.0 V, thermally driven regrowth of the SL films was observed. The results demonstrate a simple and appropriate method of optimizing topological SL films as recording media without device fabrication.