Germanium Telluride: A Chalcogenide Phase Change Material with Many Possibilities

Germanium telluride (GeTe) is a chalcogenide phase change material which is nonvolatile and changes its phase from amorphous state to a highly conductive crystalline state at approximately 180–230°C temperature, dropping the material’s resistivity by six orders of magnitude. These temperature-induced states lead to different physical and chemical properties, making it a suitable candidate for optical storage, reconfigurable circuit, high-speed switching, terahertz (THz), and satellite applications. Besides, GeTe-based devices offer complementary metal oxide-semiconductor (CMOS) compatibility and simplified, low-cost fabrication processes. In this chapter, three applications of GeTe will be discussed. They are as follows: (1) how GeTe can be utilized as DC and RF switching material with their high OFF/ON resistivity ratio, (2) how GeTe can contribute to current THz technology as split-ring resonators and modulators, and (3) effect of threshold voltage on GeTe for reconfigurable circuits.