Light-emitting Devices Of Silicon-rich Silicon Nitride Films

With the further improvement of the integration level of semiconductor chip, the traditional electrical interconnection becomes a bottleneck for the development of ultra large scale integrated circuits. Light interconnection is supposed to be an effective solution. The key point is to seek for an efficient silicon-based light source. For the past few years, silicon-rich silicon nitride (SiN_x) has received extensive attention as a candidate material for silicon-based light source because of its good luminescence properties and compatible with CMOS techniques.In this thesis, three structrure of the light-emitting devices (LEDs) based on SiNx thin films were investigated. The main results are summarized as follows:(1) Electroluminescence (EL) of light-emitting devices consited by single SiNx film wasfound centered at 600nm, which originated from the electronic transitions of E_c→≡Si^- iscentered at 600nm. Using a lightly doped p type silicon wafer as substrate would enhance the EL intensity of LEDs at the same input power, while an epitaxial p-type silicon wafer would reduce the turn on voltage.(2) Current of LEDs consited by SiN_x/a-Si/SiN_x film is increased at the same forward bias after post-annealing, meanwhile, the EL integrated intensity is enhanced at the same current density when the deposition time of a-Si layer is 60 seconds. Small amorphous Si clusters which are favorable to the tunneling of carriers formed during the annealing process, result in the raise of electronic injection and recombination efficiency of electronic-hole pairs finally.(3) EL intensity is significantly enhanced while SiO₂ electron accelerating layer is introduced to LEDs based on SiN_x film owing to the impact ionization process which inspire more carriers and result in the trend to balance the electron and hole injection. Moreover, EL intensity is closely related to the thickness of SiO₂ layer, the thinner the easier to inject the high energy electrons.