Study On The Optical And Electrical Propert-ies Of Boron-doped SiO_x Films

With the development of integrated circuit, the tranditional electrical interconnection becomes a bottleneck of the improvement of the devices. Light interconnection is an effective solution to the present predicament, and an efficient silicon based light source is the key point. In recent years, because of its good luminescence properties, efficiency and compatible with CMOS techniques, silicon-rich silicon oxide (SiOx) has received wide attention as a potential material of silicon based light source. After introducing dopant, the optical and electrical properties of SiOx films are changed and the conductivity is obviously enhanced, which arouses people’s interest.In this dissertation, we report the intrinsic and B-doped SiOx films deposited by r.f. magnetron sputtering. We disscuss the effect of Si content and B impurity on the optical and electrical properties of Si-NCs. And we obtain electrically active doping SiOx films which has obvious improvement on the conductivity. The main results are summarized as follows:The PL intensity of the intrinsic SiOx films first increases and then decreases with raising Si content, and there exists a slight red shift of the PL. With the increase of Si content, the structure and distribution of Si-NCs vary. Non-"touching" Si-NCs, which have the optical features, change to "touching" Si-NCs which do not contribute to PL. The PL intensity of the B-doped SiOx films decreases as B content increases. The reason of PL intensity decreases can be explained as follows. The large size difference between Si and B atoms engender strain-induced defects and lead to non-radiative recombination centers. And, non-radiative Auger recombination in B-doped Si-NCs is enhanced.The conductivity of the MOS device with intrinsic SiOx films first increases and then decreases with raising Si content. With the increase of Si content, the structure and distribution of Si-NCs vary. Non-"touching" Si-NCs change to "touching" Si-NCs which offer more conductive paths, and then the conductivity increases. When Si content exceeds the percolation threshold, the conduction mechianism of the system behaves as a simple disordered semiconductor, and the carriers can not transfer effectively that leads to the decrease of conductivity.With the increase of B content, the MOS device with electrically active B-doped SiOx films has a high carrier concentration and its conductivity obviously imporves. There are two factors for electrically active doping:The first one, B atom combines with Si atom in Si-NCs. The second one, Si content does not exceed the percolation threshold and the carriers can transfer effectively.