Microstructure effect on the HNO3-HF etching of LPCVD boron-doped polycrystalline silicon

F. Mansour-Bahloul , D. Bielle-Daspet , A. Peyrelavigne

The etching rate of the 50 HNO3 (70 %)-1 HF (49 %) undiluted solution was studied, for various conditions of etching-bath temperature (0 to 45 °C) and agitation, for three series of LPCVD Si layers w ~ 0.6 μm thick, deposited on oxidized Si wafers at 570 or 620 °C, and with in situ boron doping at 1020 or 1017 cm-3. The results were compared with the changes in the layer microstructure with layer series and depth Z obtained from TEM observations, RHEED patterns, Raman spectrometry and UV Reflectrometry. They evidence that the changes in the etching rate of polycrystalline Si films with film depth and deposition conditions are due to the changes in the rate-controlling-step of the etching process (from mass-transfer to surface-reaction) because of the enhanced contribution of the surface-reaction of oxidation at the Si grain boundaries.

Mots clés: boron; crystal microstructure; elemental semiconductors; etching; Raman spectra of inorganic solids; reflection high energy electron diffraction; silicon; surface chemistry; surface structure; transmission electron microscope examination of materials; visible and ultraviolet spectra of inorganic solids; semiconductor; HNO sub 3 HF etching; LPCVD; polycrystalline; etching rate; etching bath temperature; agitation; Si layers; oxidized Si wafers; layer microstructure; TEM observations; RHEED patterns; Raman spectrometry; UV Reflectrometry; rate controlling step; mass transfer; surface reaction; oxidation; Si grain boundaries; 0 to 45 degC; 570 degC; 620 degC; Si:B; HNO sub 3 HF

Domaines: Articles anciens

F. Mansour-Bahloul, D. Bielle-Daspet, A. Peyrelavigne. Microstructure effect on the HNO3-HF etching of LPCVD boron-doped polycrystalline silicon. Revue de Physique Appliquée, 1987, 22 (7), pp.671-676. ⟨10.1051/rphysap:01987002207067100⟩. ⟨jpa-00245595⟩