Articles you may be interested inAnalysis of the chemical composition and deposition mechanism of the SiO x -Cl y layer on the plasma chamber walls during silicon gate etching Environmentally benign etching process of amorphous silicon and tungsten using species evaporated from polytetrafluoroethylene and fluorinated ethylene propylene J. Vac. Sci. Technol. A 21, 302 (2003); 10.1116/1.1531131Etch characteristics of optical waveguides using inductively coupled plasmas with multidipole magnets Process variation with chamber surface condition in high density plasma reactors can seriously affect the process performance and productivity of device manufacturing. In this work, the impact of chamber surface coating on polycrystalline-silicon ͑polysilicon͒ gate etching with Cl 2 -and HBr-based plasma has been studied. The dependence of process sensitivity to surface coating on various processing conditions has been characterized and the mechanism of process shift has been analyzed. Based on the experimental results, the root cause of process sensitivity has been attributed to the change of surface recombination rate of free radicals on different chamber surfaces which leads to a variation in reactive neutral density. Under a certain discharge condition, the Cl and Br densities in a clean chamber with anodized aluminum and alumina surfaces are Ͼ60% lower than those in a seasoned chamber with silicon oxide deposition, resulting in lower polysilicon and oxide etch rate in the former case. In general, the process sensitivity to chamber surface condition depends on process regime and is higher for those processes where etching is more chemical in nature, such as processes at higher pressure and with Cl 2 -based chemistry. Processes with higher oxygen concentration and higher source power are also more sensitive due to the accelerating surface oxidation of polysilicon surface in a clean chamber. Approaches to reduce the effect of process sensitivity have been discussed.

Laser-controlled photoelectrochemical etching of III-V semiconductors using micrometer-sized illumination regions has been investigated for varying laser parameters (power, spot size, wavelength) and etching solutions. The etching has been applied to a wide variety of semiconductor doping types. The micrometer spot size of the laser can induce higher etch rates for a given intensity when compared to broad illumination. In addition, the process has micrometer-scale resolution and highly directional etch anisotropy. In this electroless process the laser etching rate is influenced by lightinduced voltage shifts in the surface potential. Finally, the dependence of the process resolution on carrier diffusion and etch depth is discussed.Light-induced aqueous etching has recently been shown to be useful for a wide range of applications in semiconductor technology. These applications include the fabrication of optical components such as lenses (1), diffraction * Electrochemical Society Active Member. gratings (2), and waveguides (3). In addition, such lightassisted etching has been considered for such operations as through-wafer-via formation for microwave field effect transistors (FETs) (4). Finally, reactions similar to those obtained in light-assisted etching have been used in the surface modification of semiconductor compounds ( 5). An

We report on deep-ultraviolet (UV), light-assisted wet etching of GaAs. The etching chemistry differs from that using visible wavelengths and all doping types of GaAs can be efficiently etched. The UV processing offers rapid etching at low, nonthermal laser intensities and permits very deep, vertical features to be made.

We present a study of deep-ultraviolet-light-enhanced (4.1 < hv < 5.1 eV) oxygen reactions on GaAs from submonolayer to several monolayers coverage. The reaction is nonthermal and does not involve gas-phase excitation or dissociation of O 2 , Our experiments show a distinct wavelength and coverage dependence for the photoenhancement. X-ray photoelectron spectroscopy has been used to examine the chemical nature of the oxygen adsorbate and the GaAs oxides in order to find intermediate reaction species and evidence of the reaction pathways. The roles of photons and photogenerated carriers in the reaction enhancement mechanism are discussed. The results indicate that a mechanism based on photoemission of electrons into the growing oxide film is most in accord with the experimental observations. Such electron emission would increase the field-driven transport of oxygen to the GaAs interface.

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