skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effects of N{sub 2}, O{sub 2}, and Ar plasma treatments on the removal of crystallized HfO{sub 2} film

Abstract

The effects of plasma treatment using Ar, N{sub 2}, and O{sub 2} on the removal of crystallized HfO{sub 2} films in a dilute HF solution were studied. The resulting damage in source and drain regions, and recess in isolation regions were also investigated. It was found that plasma nitridation with an ion energy of several hundred electron volts can lower the wet etch resistance of crystallized HfO{sub 2} films up to 70 A thick through the generation of Hf-N bonds. However, thermal nitridation did not introduce sufficient nitrogen into bulk crystallized HfO{sub 2} films to lower wet etch resistance. Plasma nitridation without bias power introduced nitrogen to the crystallized HfO{sub 2} in the region only within 10 A of the surface. The enhancement of the etch rate of crystallized HfO{sub 2} in dilute HF and the amount of recess in the active and isolation regions using N{sub 2}, O{sub 2}, and Ar plasma treatment have been evaluated. Results show that N{sub 2} plasma treatment is the most effective in enhancing the removal rate of crystallized HfO{sub 2} in dilute HF and minimizing recess on substrate among the plasmas studied.

Authors:
; ;  [1]
  1. Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)
Publication Date:
OSTI Identifier:
20776941
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films; Journal Volume: 24; Journal Issue: 1; Other Information: DOI: 10.1116/1.2141619; (c) 2006 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHEMICAL BONDS; ETCHING; FILMS; HAFNIUM OXIDES; HYDROFLUORIC ACID; NITRIDATION; NITROGEN; PLASMA; SOLUTIONS; SUBSTRATES; SURFACES

Citation Formats

Chen Jinghao, Yoo, Won Jong, and Chan, Daniel S.H.. Effects of N{sub 2}, O{sub 2}, and Ar plasma treatments on the removal of crystallized HfO{sub 2} film. United States: N. p., 2006. Web. doi:10.1116/1.2141619.
Chen Jinghao, Yoo, Won Jong, & Chan, Daniel S.H.. Effects of N{sub 2}, O{sub 2}, and Ar plasma treatments on the removal of crystallized HfO{sub 2} film. United States. doi:10.1116/1.2141619.
Chen Jinghao, Yoo, Won Jong, and Chan, Daniel S.H.. Sun . "Effects of N{sub 2}, O{sub 2}, and Ar plasma treatments on the removal of crystallized HfO{sub 2} film". United States. doi:10.1116/1.2141619.
@article{osti_20776941,
title = {Effects of N{sub 2}, O{sub 2}, and Ar plasma treatments on the removal of crystallized HfO{sub 2} film},
author = {Chen Jinghao and Yoo, Won Jong and Chan, Daniel S.H.},
abstractNote = {The effects of plasma treatment using Ar, N{sub 2}, and O{sub 2} on the removal of crystallized HfO{sub 2} films in a dilute HF solution were studied. The resulting damage in source and drain regions, and recess in isolation regions were also investigated. It was found that plasma nitridation with an ion energy of several hundred electron volts can lower the wet etch resistance of crystallized HfO{sub 2} films up to 70 A thick through the generation of Hf-N bonds. However, thermal nitridation did not introduce sufficient nitrogen into bulk crystallized HfO{sub 2} films to lower wet etch resistance. Plasma nitridation without bias power introduced nitrogen to the crystallized HfO{sub 2} in the region only within 10 A of the surface. The enhancement of the etch rate of crystallized HfO{sub 2} in dilute HF and the amount of recess in the active and isolation regions using N{sub 2}, O{sub 2}, and Ar plasma treatment have been evaluated. Results show that N{sub 2} plasma treatment is the most effective in enhancing the removal rate of crystallized HfO{sub 2} in dilute HF and minimizing recess on substrate among the plasmas studied.},
doi = {10.1116/1.2141619},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
number = 1,
volume = 24,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • We have investigated the effect of the deposition of an HfO{sub 2} thin film as a gate insulator with different O{sub 2}/(Ar + O{sub 2}) gas ratios using RF magnetron sputtering. The HfO{sub 2} thin film affected the device performance of amorphous indium–gallium–zinc oxide transistors. The performance of the fabricated transistors improved monotonously with increasing O{sub 2}/(Ar + O{sub 2}) gas ratio: at a ratio of 0.35, the field effect mobility of the amorphous InGaZnO thin film transistors was improved to 7.54 cm{sup 2}/(V s). Compared to those prepared with an O{sub 2}/(Ar + O{sub 2}) gas ratio of 0.05,more » the field effect mobility of the amorphous InGaZnO thin film transistors was increased to 1.64 cm{sup 2}/(V s) at a ratio of 0.35. This enhancement in the field effect mobility was attributed to the reduction of the root mean square roughness of the gate insulator layer, which might result from the trap states and surface scattering of the gate insulator layer at the lower O{sub 2}/(Ar + O{sub 2}) gas ratio.« less
  • A reduction of the deposition temperature is necessary for atomic layer deposition (ALD) on organic devices. HfO{sub 2} films were deposited by ALD on silicon substrates in a wide temperature range from 80 to 300 °C with tetrakis[ethylmethylamino]hafnium as metal precursor and H{sub 2}O, O{sub 3}, or an remote O{sub 2}-plasma as oxygen source. Growth rate and density were correlated to electrical properties like dielectric constant and leakage current of simple capacitor structures to evaluate the impact of different process conditions. Process optimizations were performed to reduce film imperfections visible at lower deposition temperatures. Additionally, the influence of postdeposition annealing onmore » the structural and electrical properties was studied.« less
  • In this work, the authors investigated the etching characteristics of TaN and HfO{sub 2} layers for gate stack patterning in BCl{sub 3}/Ar and BCl{sub 3}/C{sub 4}F{sub 8}/Ar inductively coupled plasmas and the effects of C{sub 4}F{sub 8} addition on the etch selectivity of the TaN to the HfO{sub 2} layer. Addition of C{sub 4}F{sub 8} gas to the BCl{sub 3}/Ar chemistry improved the TaN/HfO{sub 2} etch selectivity because adding the C{sub 4}F{sub 8} gas enhances the formation of the CF{sub x}Cl{sub y} passivation layer on HfO{sub 2} surface and decreased the HfO{sub 2} etch rate more rapidly than the TaNmore » etch rate in a disproportionate way. Reduction in the etch time for HfO{sub 2} layer also increases the TaN/HfO{sub 2} etch selectivity because the etch time gets closer to the initiation time for HfO{sub 2} etching.« less
  • This article presents experimental results on the effects of the O{sub 2} concentration on the removal efficiency of two exemplaric volatile organic compounds (VOCs): toluene (TOL) and trichloroethylene (TCE), with dielectric barrier discharges in dry Ar and N{sub 2}. For both carrier gases, there is an optimal oxygen concentration of 0.3{percent} for the removal efficiency, suggesting optimal utilization of oxygen radicals for VOC attack, rather than ozone production which has slow reaction rates with TOL and TCE. This is manifested by measurements of ozone concentrations in mixtures of Ar/O{sub 2}/TCE as a function of the oxygen concentration, showing a minimummore » at maximal removal efficiencies. All results are discussed in terms of changes in the discharge behavior, radical formation, and chemical reaction pathways with changing O{sub 2} concentration in the carrier gas. {copyright} {ital 1999 American Institute of Physics.}« less
  • The etch selectivity of HfO{sub 2} to Si reported to date is poor. To improve the selectivity, one needs to either increase the etch rate of HfO{sub 2} or decrease the etch rate of Si. In this work, the authors investigate the etch selectivity of HfO{sub 2} in Cl{sub 2}/N{sub 2} plasmas. In particular, the effects of in situ N{sub 2} plasma treatment of HfO{sub 2} and Si were investigated. The silicon substrate was exposed to nitrogen plasma and was nitrided, which was confirmed by x-ray photoelectron spectroscopy. The nitrided Si etching was suppressed in Cl{sub 2}/N{sub 2} plasmas. Themore » effectiveness of nitridation was studied with varying the plasma power, bias power, pressure, and N{sub 2} plasma exposure time. The results show that the etch resistance increased with increased power and decreased pressure. A minimum exposure time was required to obtain etch resistant property. The applied bias power increased the etch rate of Si substrate, so it should not be used during N{sub 2} plasma treatment. Fortunately, the etch rate of HfO{sub 2} was increased by the nitridation process. Therefore, HfO{sub 2}/Si selectivity can be improved by nitridation and became higher than 5 under proper exposure condition.« less