TY - CHAP AU - Bein, Márton AU - Mizsei, János ED - Bernard, Courtois ED - Marta, Rencz TI - Contracting Current Paths in Vanadium Dioxide Thin Films T2 - Proceedings of the 17th International Workshop on THERMal INvestigation of ICs and Systems (THERMINIC'11) PB - EDA Publishing Association CY - Grenoble SN - 9781457707780 PY - 2011 SP - 66 EP - 69 PG - 4 UR - https://m2.mtmt.hu/api/publication/2668775 ID - 2668775 AB - Vanadium dioxide (VO2) has been extensively investigated due to its thermal-induced metal-insulator transition (MIT) at about 67 oC; which can be lowered by doping. During the transition from semiconductor to metallic phase electrical conductivity can increase by up to 3-4 orders of magnitude, while optical reflectance can drop by almost 50%. Possible applications include thermally controlled electrical and optical switches. As the thin film is conductive optical changes can be induced electrically by Joule-heating. In this paper we present electro-optical measurements carried out on 100 nm thick VO2 thin films deposited on sapphire substrates. Phase transitions were electrically induced in contacted films and observed using an optical microscope. Strong spatial inhomogeneity has been detected: a few micron wide dark path connected the two contacts. The visible channel is a metallic area within the semiconducting film as the domain undergoes a MIT because of the Joule-heat of the flowing current. The optically observable fine structure found suggests that VO2 thin films could be used to visualize isotherms with a resolution of a few microns, similar to that of liquid crystals. Possible benefits include the simple and reliable use of the once deposited solid phase precision films and a higher resolution compared to liquid crystal thermography. LA - English DB - MTMT ER - TY - JOUR AU - Csendes, A AU - Székely, Vladimir AU - Kerecsen Istvánné Rencz, Márta TI - Thermal mapping with liquid crystal method JF - MICROELECTRONIC ENGINEERING J2 - MICROELECTRON ENG VL - 31 PY - 1996 IS - 1-4 SP - 281 EP - 290 PG - 10 SN - 0167-9317 DO - 10.1016/0167-9317(95)00350-9 UR - https://m2.mtmt.hu/api/publication/2606972 ID - 2606972 AB - Good resolution thermal mapping can be achieved by using liquid crystals. The article presents a new, high resolution automated measuring equipment, which executes the measurement and the evaluation process under computer control. The equipment was developed especially for micro-thermography of integrated circuits. The paper presents the practical aspects of the liquid crystal measuring method. Resolution and accuracy features of the method are also discussed. LA - English DB - MTMT ER -