Impact of Bottom Electrode Integration on OxRAM Arrays Variability

N.-P. Tran (1) , J. Sandrini (1) , A. Persico (1) , J.-F. Nodin (1) , T. Magis (1) , R. Crochemore (1) , N. Castellani (1) , M.-C. Cyrille (1) , G. Molas (1) , E. Nowak (1)

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

HfO$_2$-based OxRAMs with various metal stacks in the inferior VIA of bottom electrode were fabricated. We demonstrated for the first time that the metal stack of TiN PVD (physical vapour deposition), followed by an annealing step decreases the standard error of the forming voltage by 10% compared to the other variants. The related die-to-die and cell-tocell variability is greatly reduced along the wafer diameter and the LRS shows better control of the tail bits at 3$\sigma$ of the distribution. The number of failed operations over 1e4 cycles for 1k cells is reduced by a factor 3, reaching a BER of 8e-5. Finally, correlation of the cell reliability with the bottom via roughness is discussed.

Keywords: Tin; Electrodes; Voltage measurement; Annealing; Surface treatment; Resistance

Domains: Engineering Sciences [physics]; Engineering Sciences [physics]; Micro and nanotechnologies/Microelectronics

N.-P. Tran, J. Sandrini, A. Persico, J.-F. Nodin, T. Magis, et al.. Impact of Bottom Electrode Integration on OxRAM Arrays Variability. VLSI-TSA - 2020 International Symposium on VLSI Technology, Systems and Applications, Aug 2020, Hsinchu, Taiwan. pp.33-34, ⟨10.1109/VLSI-TSA48913.2020.9203694⟩. ⟨cea-03027403⟩