Experimental Study On Surface Conductance Modulation Of Itanium Oxide Bombarded By Argon Ions

The stability of high reflectivity film directly determines the whole system of laser gyroscope.The key factor affecting the stability of the film is the change of the loss under laser irradiation.When there are defects on the surface of the film,the loss increases and the surface is charged in the plasma environment.Therefore,we put forward the idea of constructing conductive channel in the multilayer film.Recently,various experimental reports have shown that the quasi-two-dimensional electron gas(2DEG)can be produced by argon ion implantation of SrTiO₃,which makes it possible for SrTiO₃ to change from an insulating state to a semiconductor state or even a metal state.The conductive layer formed by surface modification of titanium oxide and its related physical properties have also become a hot topic.HfO₂ has high dielectric constant and good contact with the substrate,and it is considered as a substitute for the next generation of gate oxides.In this thesis,the relationship between the conductivity of SrTiO₃ and titanium oxide crystal surface modified by argon ion implantation with the implantation dose was studied,and the relationship between the conductivity change and the surface chemical state was also analyzed.In addition,the resistivity of SrTiO₃ crystal conductive layer changed with time and the stabilizing effect of amorphous HfO₂ film on the resistivity of the conductive layer was emphatically studied.1.The conducting layer was prepared by injecting argon ion in SrTiO₃ and Ti O₂ single crystal.In the conducting layer on the surface of SrTiO₃ crystal,its electrical properties showed metal properties,while the temperature increased,the resistivity changed with the temperature,and the electrical properties also in line with the quasi-two-dimensional electron gas characteristics.However,in the Ti O₂ crystal,there is a complex metallic-insulation phase transition,showing a metallic property before 150K,and the resistivity increases with the increase of temperature,and decreases with the increase of temperature after 150K.At the same time,the improvement of the resistivity of titanium oxide crystals with different doses is different.With the increase of the injected energy,the surface resistivity of the samples decreases gradually at room temperature.With the increase of injection dose,the surface resistivity of the sample decreases gradually at room temperature.2.The relationship between the conductive layer of SrTiO₃ and Ti O₂ single crystal and its chemical states was studied.In the conductive layer of SrTiO₃ single crystal,Ti atoms change valence,Ti³⁺and Ti²⁺can be seen at the low binding energy,and oxygen vacancy can also be seen at the high binding energy shoulder peak.In the conductive layer on the surface of Ti O₂crystal,there is also an obvious Ti valence,Ti³⁺and Ti²⁺appear,and oxygen vacancy can also be obviously found.At the same time,with the increase of the injected energy,the relative concentration of oxygen vacancy peak area gradually increases.3.The stability of surface resistivity of SrTiO₃ in different oxygen atmospheres was studied.With the increase of time,the resistivity increases gradually,and increases the fastest in O₂ and the slowest in N₂.At the same time,the resistivity increases rapidly at the beginning of the test,but slows down as time goes on.Based on curve fitting analysis,we think that in the early stages,the surface adsorption of oxygen diffusion dominates,it into the sample surface,rapid conductive layer to the sample of oxygen vacancy"composite",through the absorption of oxygen vacancy left by electronic and occupy the oxygen vacancy clearance,makes the surface carrier concentration reduced rapidly,the resistivity increased rapidly.With the increase of the test time,the surface diffusion process slows down and tends to be stable.The bulk diffusion occupies a dominant position and the increase of the sample resistivity slows down.At the same time,the volume diffusion rate increases with the increase of the ion implantation energy.4.The surface resistivity of amorphous HfO₂ thin film SrTiO₃ crystal was studied.Firstly,the amorphous HfO₂ thin film was prepared and its surface was analyzed.SEM test showed that the growth rate was about 2.2 nm/min,and the thin film was uniform and compact.AFM test shows that the surface roughness is about 0.9nm.The XRD test shows that there is no crystal surface diffraction peak,indicating the amorphous oxide film.After that,HfO₂ was deposited on the conductive layer on the surface of SrTiO₃ crystal,the resistivity of SrTiO₃crystal decreased significantly.Only in the initial stage of the test,the resistivity increased significantly.With the increase of time,the resistivity tended to be stable and basically remained unchanged.The experimental results show that the surface amorphous HfO₂ has a good protective effect on the resistivity stability of the conductive layer.