Types Of Silicon Dioxide Research Articles

The Modelization of the Wet Etching Rate by the Segregation Boron and Phosphorus Distributions in Si/SiO<sub>2</sub>

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 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.

Silicon dioxide film with lower deposition temperature in hot-wall, single-type chamber

A lower-temperature process for the deposition of silicon dioxide was developed in a hot-wall, single-type chamber, using a gaseous mixture of SiH4 and N2O. The deposition rate was measured as a function of deposition temperature, pressure, and SiH4/N2O flow-rate ratio. At fixed SiH4/N2O, two types of silicon dioxide, which had the same deposition rate, were deposited. One was deposited at low temperature (700 °C) and high pressure (20 Torr), and the other was deposited at high temperature (850 °C) and low pressure (2.5 Torr). The film characteristics of the two types of silicon dioxide were compared. The results revealed that the low-temperature film exhibited similar characteristics to those of the high-temperature film. Therefore, the current high-temperature process can be replaced by a low-temperature process to achieve low thermal budget in semiconductor device processing.

Ionic transport in fused silica and thin thermal SiO2 films

High temperature ionic conductivity of fused silica and thin SiO2 films has been investigated in the temperature ranges 700–1400 and 570–830 K respectively by impedance spectroscopy measurements. The results are in agreement with the existence of extrinsic mechanisms in the ionic transport of both types of silicon dioxide, due to the presence of dissociated sodium ions. The numerical analysis of the experimental results led to values of 1.3 and 0.6 eV for the dissociation and migration energies, respectively. No influence of hydrogen content on alkali transport was found by considering wet and dry samples, at variance with results previously obtained on crystalline quartz.

Micromechanical structures for electron- and ion-beam irradiation phenomena

Micromechanical structures are used to investigate the effects of electron- and ion-beam irradiation on silicon dioxide. The devices are simple cantilever beams (50 μm long) fabricated from different types of silicon dioxide and integrated with two parallel driving electrodes. The electrically floating silicon dioxide beams oscillate only under electron-beam irradiation with an ac voltage applied to the driving electrodes at resonance. Accumulated charge produced by electron-beam irradiation in a scanning electron microscope (SEM) produces a driving force between the cantilever beam and the driving electrode. A time-resolved SEM technique is used to determine the resonant frequencies of these micro-cantilever beams. Electron- and ion-beam damage is measured by detecting the shift in the resonant frequency as a function of the irradiation time (electron-beam dose or sputtering time). Experimental results show that the resonant frequency of the silicon dioxide cantilever beam increases under electron-beam irradiation; this frequency rise indicates that material hardening or mass loss or both occur when the cantilever is subjected to electron-beam irradiation. We also observed differences in the rate of change of the frequency shift between thermally grown silicon dioxide films and plasma enhanced chemical vapor deposition silicon dioxide films. Under argon sputtering, the resonant frequency of the silicon dioxide cantilever beam decreases due to the change in the dimensions and mass of the cantilever beam caused by sputtering.