The Atomic Layer Deposition Technique for the Fabrication of Memristive Devices: Impact of the Precursor on Pre-deposited Stack Materials

C. QUINTEROS; A. HARDTDEGEN; M. BARELLA; F. GOLMAR; F. PALUMBO; J. CURIALE; S. HOFFMANN-EIFERT; P. LEVY

New Uses of Micro and Nanomaterials

IntechOpen

Lugar: London; Año: 2018; p. 3 - 23

Atomic layer deposition (ALD) is a standard technique employed to grow thin-film oxides for a variety of applications. We describe the technique and demonstrate its use for obtaining memristive devices. The metal/insulator/metal stack is fabricated by mean sof ALD-grown HfO2, deposited on top of a highly doped Si substrate with an SiO2 film and a Ti electrode. Enhanced device capabilities (forming free, self-limiting current, non-crossing hysteretic current-voltage features) are presented and discussed. Careful analysis of the stack structure by means of X-ray reflectometry, atomic force microscopy, and secondary ion mass spectroscopy revealed a modification of the device stack from the intended sequence, HfO2/Ti/SiO2/Si. Analytical studies unravel an oxidation of the Tilayer which is addressed for the use of the ozone precursor in the HfO2 ALD process. A new deposition process and the model deduced from impedance measurements supportour hypothesis: the role played by ozone on the previously deposited Ti layer is found to determine the overall features of the device. Besides, these ALD-tailored multifunctionaldevices exhibit rectification capability and long enough retention time to deserve theiruse as memory cells in a crossbar architecture and multibit approach, envisaging other potential applications.