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Undoped silicate glass deposited using the tetraethylorthosilicate (TEOS) and ozone thermal reaction has been selected as one of the candidates for shallow trench isolation applications. As a replacement for existing low pressure or atmospheric pressure chemical vapor deposition processes for device dimensions below 0.25 μm, TEOS/ozone films deposited at high temperature (>550°C) exhibit the superior qualities in terms of void‐free trench fill. In this paper, we present some characterization of the silicon oxide film deposited in the subatmospheric pressure regime using TEOS/ozone chemistry, aimed at developing a high‐quality dielectric film to meet shallow trench isolation gap‐fill requirements. It is also identified that low ozone/TEOS ratio reduces surface and pattern sensitivity. Therefore, no additional treatment or predeposition is necessary. Moreover, to enhance the etch resistance of the silicon oxide, the as‐deposited film is annealed at high temperature for densification and bond reconstruction. © 1999 The Electrochemical Society. All rights reserved.

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Water-free inherent selective deposition of TiO2 on Si and SiO2 in preference to SiCOH has been studied via atomic layer deposition (ALD) and pulsed chemical vapor deposition (CVD). SiCOH is a nonreactive low-k dielectric material, consisting of highly porous alkylated SiO2. Water-free deposition was studied to protect SiCOH and increase selectivity. The titanium precursor used in all studies was Ti­(O i Pr)4 [titanium­(IV) isopropoxide] and contains four oxygen atoms enabling it to form TiO2 through single-precursor CVD. At 250 °C substrate temperature, selective water-free ALD of TiO2 using Ti­(O i Pr)4 and either acetic acid (AcOH) or formic acid (HCO2H) as a second precursor was studied. By both ALD processes, around 2 nm of TiO2 was deposited on Si and SiO2 without any deposition on SiCOH. The TiO2 ALD films had a root-mean-square roughness of 2–3 Å. In situ X-ray photoelectron spectroscopy showed that Ti­(O i Pr)4 + AcOH ALD occurred via ligand exchange between −O i Pr and AcO–. ALD with formic acid, which is a 10× stronger proton donor than acetic acid, displayed similar selectivity but with a 10× higher growth rate than ALD with acetic acid. Single-precursor pulsed CVD with Ti­(O i Pr)4 was also studied at 250 and 295 °C substrate temperatures. At 250 °C, TiO2 growth on all substrates was minuscule (<1 nm for 400 pulses). Single-precursor pulsed CVD (2000 pulses) at 295 °C displayed the highest selectivity among all processes studied: 16.9 and 40.1 nm TiO2 molecules were deposited on Si and SiO2, respectively, while less than a monolayer of TiO2 was deposited on SiCOH. The pulsed CVD at 295 °C showed ∼20 nm of selective TiO2 deposition on nanoscale patterned samples. It is expected that the selective TiO2 CVD can be applicable in the nanoscale patterning process in metal-oxide-semiconductor field-effect transistor fabrication.

Selective and smooth dielectric-on-dielectric was achieved by water-free single-precursor chemical vapor deposition (CVD) processes with the help of aniline passivation. Aniline selective passivation was demonstrated on W surfaces in preference to SiO 2 at 250, 300, and 330 °C. After aniline passivation, selective HfO 2 , Al 2 O 3 , and TiO 2 were deposited only on the HF-cleaned SiO 2 surface by water-free single-precursor CVD using hafnium tert-butoxide Hf(O t Bu) 4 , aluminum-tri-sec-butoxide (ATSB), and titanium isopropoxide Ti(O i Pr) 4 as the precursor reactants, respectively. Hf(O t Bu) 4 and Ti(O i Pr) 4 single-precursor CVD was carried out at 300 °C, while the ATSB CVD process was conducted at 330 °C. HfO 2 and Al 2 O 3 nanoselectivity tests were performed on W/ SiO 2 patterned samples. Transmission electron microscopy images of the W/SiO 2 patterned samples after deposition demonstrated nanoselectivity and low surface roughness of HfO 2 and Al 2 O 3 deposition on the SiO 2 regions only.