Plasma Immersion Into The Modification Of Semiconductor Materials

Plasma immersion ion implantation (PⅢ) is a new kind of technique which is widely used for the surface property improvement because of its non-line-of-sight character. PⅢwas first used for the metallurgical and tribological engineering, and then it was used in the field of bio-polymer macromolecular materials. Besides of these applications, PⅢalso shows the technology suitable in semiconductor and microelectronics processing. In this paper, we constructed the PⅢequipment and did some research work. We used the PⅢtechnique to fabricate nitrogen-doping ZnO thin film by nitrogen ion implantation. Also we simulated the SIMOX process in the SOI fabrication and did some research work.We proposed a new method to calibrate the ion dose implanted in PⅢ. Different from the conditional dose calculation, the new method was based on the measurement of loop current, so we called it current measurement method (CMM). A key issue in CMM is to eliminate the secondary electron in the integral of the current and get the ion dose implanted. When the pulse duration changed during the PⅢprocess, the original calculation model has some problems and it was modified referring to the CMM results.In this paper, PⅢwas used for the application of p-type ZnO fabrication. The ZnO thin film was prepared by plused laser deposition (PLD). The samples were nitrogen doped by PⅢand followed with a rapid thermal annealing (RTA) process at 800℃. Based on the result of testing and analysis, the nitrogen doped in ZnO were tend to gathered and formed as Zn(N3)2 which was not beneficial for the p-type ZnO fabrication. Thus, we set the nitrogen doping in PⅢprocess with a variable voltage and get the nitrogen-doped p-type ZnO films by PⅢ. The p-type ZnO showed p-type conductivity with a hole concentration of 9.74×1014 cm-3 and a mobility of 6.52 cm2·V-1·s-1.We also fabricated phosphorus-doped p-type ZnO for contrast. The ZnO films were prepared by PLD with different concentration of P2O5. It was found that, the crystallinity of ZnO could be improved with an appropriate doping of P2O5. After the treatment of annealing, the ZnO with a P2O5 concentration of 2 mol% showed p-type conductivity after annealing, with a hole concentration of 1.70×1017 cm-3 and a mobility of 13.00 cm2·V-1·s-1. Similarly, the mechanism of the p-type P-doping ZnO was studied. The PⅢtechnique was also used to simulate the SIMOX process in this paper. The wafer was implanted of oxygen by PⅢwith different parameters, and then it was annealed in a tube at the tempreture of 1300℃. We discovered that the thickness of the oxide layer is related with the annealing atmosphere and the implanting voltage. The surface oxide layer could be improved by the annealing process. Also the defects in the layer were studied before or after the annealing. We concluded the transformations and the reasons.