Hamburg 2001 – scientific programme
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HL: Halbleiterphysik
HL 24: Poster II
HL 24.87: Poster
Thursday, March 29, 2001, 10:30–19:00, Rang S\ 3
Thickness evaluation of ultra-thin SiO2 layers for ULSI applications — •Andreas Kerber1,2, Joze Bevk2, Tom Sorsch2, and Erich Vass1 — 1Institut für Experimentalphysik, Univ. Innsbruck, A-6020 Innsbruck — 2Bell Laboratories, Lucent Technologies, 600 Mountain Ave., Murray Hill, NJ 07974, USA
Accurate thickness determination of ultra-thin gate oxides, which is critically important for device simulation and characterization, presents considerable experimental challenge. In this study, we have grown state of the art 1.0 - 4.0 nm thick SiO2 oxides on p-type epi-Si substrates using either furnace or Rapid Thermal Oxidation techniques. All oxides have been analyzed in detail using the contact-less Q-V method (Quantox tool), optical and electrical (Ig-Vg and C-V) methods. The data obtained with the electrical and optical method are found to be in good agreement, irrespective of the gate oxidation process. By contrast the oxide thickness determination obtained by means of the Quantox tool depends sensitively on the oxidation technique and processing conditions. With decreasing oxide thickness the uncertainty in the reading becomes larger. Below 1.5 nm the direct tunneling leakage current leads to unreliable oxide data.