Electric conduction of silicon nitride induced by Si ion implantation

We have examined the change of electric conduction of silicon nitride induc ed by MeV Si ion implantation. 2 MeV Si- ions were implanted at the doses f rom 1 x 10(14) to 3 x 10(17) ions/cm(2) in 12 steps, by measuring the resis tance using de-constant voltage method between two deposited Mo thin films as electrodes on the sample. Temperature during implantation was 370-530 or 600 K without or with heater. Up to the dose of 2 x 10(16) or 8 x 10(15) i ons/cm(2) for without or with heater, sheet resistance was larger than 10(9 ) Omega/square. The resistance decreased dramatically with increasing dose and it became less than 10(5) Omega/square at doses over 1 x 10(17) ions/cm (2). Saturation of conductivity over the dose of 1 x 10(17) ions/ cm(2) was clear with the heater. Temperature dependence of conductivity indicates th at the conductor is as semiconductor. After annealing up to 1000 K, the con ductivity increased; however, it decreased beyond 1150 K and it became almo st non-conductive at 1500 K. The electric conduction induced by Si ion impl antation occurs via a variable-range hopping process and closely related to defects and their behavior. (C) 2000 Elsevier Science B.V. All rights rese rved.