Study of silicon contamination and near-surface damage caused by CF4/H2 reactive ion etching

Abstract

Silicon surfaces which had been exposed to a CF4 /H2 plasma have been characterized by x-ray photoelectron spectroscopy, ellipsometry, He ion channeling, and H profiling techniques. Plasma exposure leads to the deposition of a thin (∼30 Å thick) C,F-polymeric layer. Hydrogen and/or damage (displaced Si atoms) can be detected in the near-surface region up to a depth in excess of 400 Å from the Si surface.

Investigation of Reactive‐Ion‐Etching‐Related Fluorocarbon Film Deposition onto Silicon and a New Method for Surface Residue Removal

“…The great difference in Si disorder measured after RIE for 1 rain and 10 min overetched samples (Table I), is virtually eliminated by the 30 rain O~ annealing at 400~ Photoemission measurements.--All plasma exposed Si substrates exhibited surface residues consisting primarily of C and F species, in agreement with previous reports (4,6). The chemical state of the surface impurities was investigated by x-ray photoemission measurements.…”

“…The two spectra shown in the lower half of Fig. 1 are similar to spectra reported previously (4): The BHF control sample shows the Si surface peak and an O related peak due to the native oxide layer. The spectrum obtained with a 1 rain overetched sample differs from the control, in that a much greater Si surface peak, indicative of near-surface lattice disorder, and an increased background level to the left of the Si surface peak are observed.…”

Dynamics of light-induced separation of gases

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] As to damages of vertical Si walls, effects of energetic H þ ions at oblique incidence need to be better understood. In this study, we have used a multi-beam system to study Si etching properties by irradiation of ions and radical species associated with etching processes of vertical Si channels by hydrogen halide (HCl and HBr) plasmas.…”

Optical Observation of Deep Bulk Damage in Amorphous Perfluorocarbon Films Produced by UV Photons Emitted from Low-Pressure Argon Plasma

“…Compared with other energetic particles in plasma such as ions and electrons, UV photons have a much larger depth of penetration into transparent materials and can induce defects in the bulk region several hundred nanometers below the surface [18][19][20]. In past studies, various analytical methods have been employed for the detection and characterization of plasma-induced damage, including X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ellipsometry [4,[9][10][11][12][13][14]19,20]. Indeed, these approaches are very useful for studying near-surface damage produced by ion bombardment, but not for detecting very slight damage generated deep in the bulk.…”

“…Soon after the development of reactive ion etching [1,2], plasma-induced damage such as gate oxide breakdown due to charge build-up and lattice defects induced by high-energy ion bombardment were reported [3][4][5]. When magnetized high-density plasma etchers such as electron cyclotron resonance (ECR) plasma etchers and magnetically enhanced reactive ion etchers (MERIEs) came into practical use in the late 1980s, intensive researches were carried out to overcome the problem of gate oxide breakdown originating from the poor plasma uniformity over a wafer.…”