In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2020-02, No. 23 ( 2020-11-23), p. 1688-1688
Abstract:
Ferroelectrics have retrieved great interest since the discovery of a ferroelectric phase in HfO 2 . 1 Especially, ferroelectric Hf 0.5 Zr 0.5 O 2 (HZO) thin films have studied for application as a non-volatile memory and field-effect transistor, due to their high scalability and compatibility with CMOS process. 2 In our previous work, we have achieved a low thermal budget process (400 °C) by controlling the tensile stress from the TiN electrode during the annealing process. 3 Moreover, the TiN electrode can act as a barrier layer against hydrogen diffusion, therefore, the HZO films using the TiN electrodes can prevent degradation of the ferroelectric properties from hydrogen incorporation. However, during the deposition of HZO film using atomic layer deposition (ALD), the choice of oxygen source can affect the residue in the deposited film. When hydrogen-related substances are used as the oxygen source, the ferroelectric properties can be altered by the residues remaining in the HZO film. In this study, we adopted various oxygen sources such as H 2 O, deuterium oxide (D 2 O), and O 3 , for the investigation of hydrogen effect on the ferroelectric properties of the ALD-HZO films. The HZO films were deposited on the TiN bottom electrode by ALD using Hf[N(CH 3 ) 2 ] 4 (TDMA-Hf) and Zr[N(CH 3 ) 2 ] 4 (TDMA-Zr) as the precursors of Hf and Zr, while H 2 O, D 2 O, or O 3 as the oxidant. After the TiN top electrode was deposited, rapid thermal annealing was done, and metal-insulator-metal capacitors were fabricated using a Pd/Au hard mask and wet etch process. The HZO films exhibited the formation of a non-centrosymmetric orthorhombic phase which is origin of the ferroelectricity, without consideration for the oxygen sources. 4 However, it was confirmed that the ferroelectricity of the HZO film deposited with the oxygen source including hydrogen such as H 2 O and D 2 O, was degraded due to the more incorporation with hydrogen. As a result, the ferroelectric polarization of H 2 O-, and D 2 O-based HZO was lower than that of O 3 -based HZO. Simultaneously, the H 2 O- and D 2 O-based HZO exhibited higher leakage current than that of O 3 -based HZO. The results strongly suggest that the suppression of hydrogen incorporation is important to apply ALD-HZO films for next-generation memory application. This work is supported by the National Research Foundation of Korea (NRF) grant (No. NRF-2019R1F1A1059972), Brain Pool Program (No. 2019H1D3A2A01101691), and the Fostering Global Talents for Innovative Growth Program (No. P0008750). 1 T. S. Böscke, et al., Appl. Phys. Lett. 99 , 102903 (2011). 2 S.J. Kim, et al., Appl. Phys. Lett. 113 , 182903 (2018). 3 S.J. Kim, et al., Appl. Phys. Lett. 111 , 242901 (2017). 4 S.J. Kim, et al., JOM 71 , 246 (2019). Figure 1
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2020-02231688mtgabs
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2020
detail.hit.zdb_id:
2438749-6
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