The Modelization of the Wet Etching Rate by the Segregation Boron and Phosphorus Distributions in Si/SiO₂

This study investigated the effects of doping on the etching of SiO₂ and in particular on the etched edge (parts). We have modelized and optimized using experimental data the etching rate of SiO₂. The effects of temperature and oxide nature are factors taken into account in the modelization. The optimization of temperature permits to define the ideal temperature to be used in order to approach anisotropy and to permit repeatability to the etching process in industry. The modelization is applied on three types of silicon dioxide. It is applied on nondoped, n-doped and p-doped SiO₂. The role of the work is to find a model using empirical relationships based on experimental results, to calculate the SiO₂ etch rate depending on the type of doping, and temperature. The commented results are based on the segregation at Si/SiO₂. We have developed a “theory” based on an empirical equation which modelizes the etch rate in non doped SiO₂, to modelize it for those n-doped and p-doped. This “theory” stipulates that the etch rate in doped SiO₂ can be predicted by knowing the etch rate in nondoped one. Thus, we have extracted an entity what we called "segregation proportionality", proportional to the diffusion-segregation boron and phosphorus distributions in the silicon dioxide-silicon, and which can be physically and chemically explained.