Cl2 Plasma — Si Surface Interactions in Plasma Etching: X-ray Photoelectron Spectroscopy After Etching, and Optical and Mass Spectrometry Methods During Etching

摘要: The interaction of a chlorine plasma with Si(100) surface has been investigated by angle resolved x-ray photoelectron spectroscopy (XPS), laser-induced thermal desorption fluorescence detection (LD-LIF), optical emission, and mass spectrometry. From XPS, it was found that the amount incorporated at Si increases ion energy, doesn’t change long exposure to plasma. Chlorine is present solely as SiClx (x = 1−3) average relative coverages [SiCl]: [SiCl2]: [SiCl3] ≌ 1: 0.33: 0.1. These don’t depend strongly on energy between ∼50 300 eV. Moreover, there substantial disordered within chlorinated layer high reflected in broadening 99.4 eV peak appearance shoulder 98.8 eV, ascribed dangling bond. modeling angle-resolved signal intensities Si-chloride species function XPS take-off angle, thicknesses 20–35 A 6–10 were derived for bias voltages −240 0 VDC, respectively. total Cl content these layers increased from 1.6×l015 Cl/cm2 0V 3.0×l015 -240 VDC bias. This shows top predominantly SiCl2 SiCl3, while just below surface, mainly SiCl are present. Laser-induced used measure Cl-coverage real time. measurements, addition time ellipsometry showed during etching stable when extinguished gas pumped away.