AVS 47th International Symposium
    Semiconductors Wednesday Sessions
       Session SC+EL+SS-WeM

Paper SC+EL+SS-WeM6
Reaction Mechanism of Si(100) Etching by Mass- and Energy-Selected Cl+ Beams

Wednesday, October 4, 2000, 10:00 am, Room 306

Session: Passivation and Etching of Semiconductors
Presenter: S.M. Lee, University of Houston
Authors: S.M. Lee, University of Houston
M. Lu, University of Houston
J.W. Rabalais, University of Houston
Correspondent: Click to Email
Plasma etching of semiconductor materials is a standard manufacturing technique used in integrated semiconductor industries. Due to the high operational pressures used in this process, it is difficult to study the basic etching mechanism. While plasma etching is a dynamic process, many studies have been done on the more static systems using analysis techniques like temperature programmed desorption (TPD). In this work, the kinetic energy and temperature dependencies of Cl+ beam etching of Si (100) have been studied by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), reflection high energy electron deflection (RHEED), and positive and negative energy-filtered secondary ion detection. Ion kinetic energies were varied over the hyperthermal range of 1 - 500 eV and sample temperatures were varied over the 25 - 700° C range. Chemical etching dominates in the low energy range, while both chemical and physical etching processes are prevalent at the higher energies. Both the AES and XPS results demonstrate that the amount of Cl deposited on the surface is a strong function of the ion energy. The RHEED study of the surface crystallinity clearly showed the existence of synergetic effects due to simultaneous ion bombardment and annealing. A nearly ideal (2x1) surface reconstruction was obtained under the conditions of 100 eV Cl+ etching at 600°C. AES analysis demonstrated that the main source of surface disordering at lower temperatures and lower kinetic energies is residual Cl in the surface region. The etching products, the kinetic energy distribution of each species, and the critical kinetic energy for the etching process have been measured for different temperatures by using the positive and negative ion detector. The overall reaction mechanism is discussed based on the results obtained.