Dry etching of TaN/HfO{sub 2} gate-stack structure in BCl{sub 3}/Ar/O{sub 2} inductively coupled plasmas
- School of Materials Science and Engineering, Sungkyunkwan University, Suwon, Kyunggi-do 440-746 (Korea, Republic of) and Center for Advanced Plasma Surface Technology, Sungkyunkwan University, Suwon, Kyunggi-do 440-746 (Korea)
In this work, etching characteristics of TaN(200 nm)/HfO{sub 2}(80 nm) gate-stack structures on Si substrate were investigated by varying the process parameters such as BCl{sub 3}/(BCl{sub 3}+Ar+O{sub 2}) gas mixing ratio (Q), top-electrode power, dc self-bias voltage (V{sub dc}), and overetch time in an inductively coupled plasma etcher. To understand the role of the etch gas chemistry, we measure the relative changes in the optical emission intensity of ions and radicals in the plasma as well as in the chemical binding states of the etched TaN surfaces. We used optical emission spectroscopy and x-ray photoelectron spectroscopy respectively. The results showed that BCl{sub 3}/Ar/O{sub 2} plasma is more effective in etching the oxidized TaN than Cl{sub 2}/Ar/O{sub 2} or HBr/Ar/O{sub 2} plasma. It is believed that the B radical species removes the oxygen atoms on the oxidized TaN surface more effectively by forming volatile boron-oxygen-chlorine compounds, such as trichloroboroxin (BOCl){sub 3}), boron oxychloride (BOCl), and boron dioxide. The measurement data also indicated that high etch selectivities of the TaN to the HfO{sub 2} layer could be obtained at the low V{sub dc}, high top-electrode power, and shorter overetch time.
- OSTI ID:
- 20777324
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 24, Issue 4; Other Information: DOI: 10.1116/1.2210944; (c) 2006 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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