A team of Indian scientists has developed a memory device with excellent switching characteristics and low power requirements for data storage applications.
Resistive memory devices with an insulating film sandwiched between the electrodes can meet the needs of high-performance, high-density memories with low power requirements for data storage, the Ministry of Science and Technology said in a statement. press release published on Friday 16 July.
They are devices with resistive switching characteristics which refer to the physical phenomena in which a dielectric (electrical insulator which can be polarized by an applied electric current) suddenly changes its resistance (at two terminals) under the action of a strong current.
Although such devices have been studied intensively to meet the huge technological demands in terms of performance, several technical challenges persist and pose major challenges to their commercialization, the ministry said.
Tremendous efforts are being made by scientists to design resistive-switched memory devices that are non-volatile, reliable and far more efficient than existing silicon-based flash memory technology, he added.
Swathi SP and Dr. S Angappane of the Center for Nano and Soft Matter Sciences (CeNS), an autonomous institution of the Department of Science and Technology of the central government, have developed a low-power memory device with excellent switching characteristics from the chemical hafnium oxide, a silicon oxide substitute, for data storage applications, the ministry said.
They used hafnium oxide (HfO2), an insulator that can be polarized upon application of an electric current as an insulating layer. The team prepared an HfO2 films by a method called sputter deposition, a physical vapor deposition technique in which energetic ions are used to remove atoms or molecules of the desired “target” material and deposit them onto a substrate.
The HfO2 The film’s resistive switching characteristics could be further improved by adjusting the growth temperature and annealing conditions – a heat treatment process that changes the physical and sometimes chemical properties of a material to increase ductility and reduce hardness for the make it more manageable, the ministry said.
The team found that a higher concentration of oxygen vacancies (loss of oxygen from their respective positions in the crystal lattice) are created when these films are subjected to a heat treatment process called annealing, a- he added.
Oxygen gaps play a critical role in creating conditions for low power operations. In addition, heat treatment also influenced the crystal behavior and defect density of hafnium oxide films, thereby affecting resistive switching parameters and device performance.
Besides, the devices also showed good endurance and high retention, the ministry said.
The research, published in the Journal of Alloys and Compounds, can contribute to the development of more efficient, viable and reliable resistive memory devices in the future.
CeNS researchers are converting these resistive memory devices into miniature forms. The team is investigating brain-inspired functionality in these memory devices and exploring the possibility of integrating the memory device with other potential sensors to bring out its multifunctional capabilities.