IN-SITU DC-PLASMA CLEANING OF SILICON SURFACES

The native oxide and carbon contamination on silicon wafers are remove d in situ by a direct current H/Ar-plasma cleaning process. The residu al contamination after the surface cleaning lies under the detection l imit of secondary ion mass spectroscopy (SIMS). However, scanning tunn eling microscope (STM) measurements show a surface roughness with a pe ak-to-peak amplitude of 4 nm on a lateral scale of 20 nm. Photoemissio n results (UPS) reveal the dangling bonds to be saturated with hydroge n. Upon annealing, reflection high energy electron diffraction (RHEED) and thermal desorption spectroscopy (TDS) show that the surfaces flat ten after the final hydrogen desorption step at temperatures of 450-50 0 degrees C.