Oxidation of etched silicon in air at room temperature; Measurements with ultrasoft X-ray photoelectron spectroscopy (ESCA) and neutron activation analysis

The oxide growth rate for p-type Si〈100〉 crystals after HF etching in air at room temperature was measured for exposures betwen 3 min and ≈ 10³ min after etching. The oxide thicknesses were determined with traditional Al Kα excited XPS and two nontraditional methods — especially suited for very thin layers: Zr Mζ excited XPS and neutron activation analysis (NAA). The oxide thicknesses (mainly SiO_x with x < 2) lie between 0.1 and 0.55 nm with a logarithmic growth rate of ≈ 0.2 nm/decade.