Abstract
A Fenton reaction and a corrosion inhibition strategy were designed for enhancing the polishing rate and achieving a corrosion-free Ge1Sb4Te5 film surface during chemical-mechanical planarization (CMP) of three-dimensional (3D) cross-point phase-change random-access memory (PCRAM) cells and 3D cross-point synaptic arrays. The Fenton reaction was conducted with 1,3-propylenediamine tetraacetic acid, ferric ammonium salt (PDTA–Fe) and H2O2. The chemical oxidation degree of GeO2, Sb2O3, and TeO2 evidently increased with the PDTA–Fe concentration in the CMP slurry, such that the polishing rate of the Ge1Sb4Te5 film surface linearly increased with the PDTA–Fe concentration. The addition of a corrosion inhibitor having protonated amine functional groups in the CMP slurry remarkably suppressed the corrosion degree of the Ge1Sb4Te5 film surface after CMP; i.e., the corrosion current of the Ge1Sb4Te5 film surface linearly decreased as the corrosion inhibitor concentration increased. Thus, the proposed Fenton reaction and corrosion inhibitor in the Ge1Sb4Te5 film surface CMP slurry could achieve an almost recess-free Ge1Sb4Te5 film surface of the confined-PCRAM cells, having an aspect ratio of 60-nm-height to 4-nm-diameter after CMP.
Highlights
Memory semiconductor device technologies have evolved to achieve fast switching, low-power consumption, and low memory bit-cost via the scaling-down of memory cells
The slurries used in our experiment were composed of 1-wt% 70-nm colloidal silica abrasives, 1-wt% oxidant H2O2, 0.01~0.05-wt% PDTA–Fe, and 0~0.09-wt% PEI, which was titrated at pH 2 using HNO3
These results indicate that the addition of a corrosion inhibitor (i.e., PEI) in the chemical-mechanical planarization (CMP) slurry suppresses the degree of corrosion-induced surface roughness
Summary
Memory semiconductor device technologies have evolved to achieve fast switching, low-power consumption, and low memory bit-cost via the scaling-down of memory cells. Two types of memory devices have been classified in terms of switching speed, power consumption, and cost per bit: dynamic random-access memory (DRAM) and three-dimensional (3D) NAND flash memory [1,2,3]. 3D cross-point PCRAM cells have been fabricated, and PCRAM-cells have a confined memory cell structure and a chalcogenide-based nonlinear-selector vertically stacked on the confined memory cell. A chalcogenidebased nonlinear-selector stacked vertically on the confined memory cell is necessary for suppressing an integrated leakage current in a memory cell array
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
