Characterizing HfO2-Based Ferroelectric Tunnel Junction in Cryogenic Temperature

Since the discovery of ferroelectric properties in doped HfO2, various types of memory devices have emerged based on this novel material. Especially, the ferroelectric tunnel junction (FTJ) has gained considerable attention for selector-less crossbar array. Although various studies have been carried out for the HfO2-based FTJs, there are no investigations of them at a cryogenic temperature. While cryogenic memories are getting increasing attentions for diverse applications from high-performance computing to aerospace electronics, exploring the FTJ at cryogenic temperature is particularly interesting because it has been known for relatively poor retention characteristics and endurance at room temperature (RT). For the first time, we characterize the HfO2-based FTJ at cryogenic temperature down to 77 K. It was found that both the retention and endurance characteristics become greatly improved at 77 K. Furthermore, the read voltage was found to be critical for optimized performance in terms of ON-current, OFF-current, and their ratio at 77 K.