Abstract
The difference in electrical and optical properties between the amorphous and crystalline states of phase change materials (PCMs) makes them useful and fascinating to study. PCMs have been widely used in optical storage and current research on PCMs focuses on their applications in electronic storage and reconfigurable photonics. PCMs could pave the way for new forms of computing and new technologies, and the ability to switch PCMs quickly and efficiently is important to the successful development of these technologies. This work focuses on using external heater to reversibly switch PCMs, particularly Ge2Sb2Te5 (GST225), which is a widely studied PCM. The purpose of this work is to demonstrate the use of a generic microheater in switching PCMs. These generic heaters can be useful in facilitating the studies of the material properties of PCMs and be used in certain devices, such as PCM-based waveguides. The designed microheater should be easy to fabricate using CMOS fabrication processes and versatile enough to be used for different applications and different PCMs. Therefore the external heater is made up of a single layer NiCrSi alloy, which will be subjected to electrical pulses. In this work, the behaviour of the microheater was simulated in COMSOL Multiphysics. The switching of GST225 and crystallization of Sb2S3 using the fabricated microheaters were demonstrated as well, although with some limitations. Therefore, the design and implementation of generic microheaters to switch PCMs appear to be possible when given the appropriate electrical pulses.