Low temperature, high quality silicon dioxide thin films deposited using tetramethylsilane (tms)

摘要

Silicon dioxide thin films have been deposited at temperatures from 40 DEG C. to 250 DEG C. by plasma enhanced chemical vapor deposition (PECVD) using tetramethylsilane (TMS) as the silicon containing precursor. The properties of the PECVD TMS oxides (PETMS-Oxs) were analyzed with Fourier TransformInfrared (FTIR) transmissionspectroscopy, BOEand P-etch rates and both current-voltage (I-V) and capacitance-voltage (C-V) electrical characterization. It was found that the deposition rate for films produced from TMS increased with decreasing temperature; that the -OH inclusions could be affected by TMS flow rate; and that He dilution rate affected trapping for films produced over the temperature range explored. At both 130 DEG C. and 250 DEG C., deposition conditions were identified which formed high quality as-deposited oxide films. Under the best conditions, unannealed Al/PETMS-Ox/c-Si capacitor structures displayed flat band voltages of Vfb -2.9 V and breakdown fields (Vbd) in excess of 8 MV/cm. These PETMS-Ox films also show low leakage current densities <10-9 A/cm2 which can be maintained up to fields in excess of 4.5 MV/cm. The PETMS oxide electrical quality and process simplicity combined to make an attractive oxide deposition technology for low temperature, large area applications.