Low Temperature High Quality Growth of Silicon-Dioxide Using Oxygenation of Hydrogenation-Assisted Nano-Structured Silicon Thin Films

摘要

We report a low temperature high quality oxide growth of nano-structured silicon thin films on silicon substrates obtained through a hydrogenation-assisted PECVD technique followed by a plasma enhanced oxidation process. A 100nm-thick electron-beam evaporated a-Si layer was hydrogenated at a plasma power of 2W/cm~2 and a temperature of 250°C, followed by a post treatment at a temperature of 300°C for 30 min. with the plasma “off”. Nano-crystalline silicon layers were obtained through this process with an average grain size of less than 5nm, which their grain size and porosity could be well controlled by process conditions. After the hydrogenation process, a plasma oxidation step was performed in an RF-PECVD for an extended period of two hours. The treated layers were investigated and compared with respect to their electrical, optical and stoichiometrical properties by means of Ellipsometry, transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and by current voltage and capacitance voltage measurements on metal-oxidesemiconductor (MOS) structures.