Growth studies and characterization of silicon nitride thin films deposited by alternating exposures to Si2Cl6 and NH3

We deposited silicon nitride films by alternating exposures to Si2Cl6 and NH3 in a cold-wall reactor, and the growth rate and characteristics were studied with varying process temperature and reactant exposures. The physical and electrical properties of the films were also investigated in comparison with other silicon nitride films. The deposition reaction was self-limiting at process temperature of 515 and 557 °C, and the growth rates were 0.24 and 0.28 nm/cycle with Si2Cl6 exposure over 2 × 108 L. These growth rates with Si2Cl6 are higher than that with SiH2Cl2, and are obtained with reactant exposures lower than those of the SiH2Cl2 case. At process temperature of 573 °C where the wafer temperature during Si2Cl6 pulse is 513 °C, the growth rate increased with Si2Cl6 exposure owing to thermal deposition of Si2Cl6. The deposited films are nonstoichiometric SiN, and were easily oxidized by air exposure to contain 7–8 at.% of oxygen in the bulk film. The deposition by using Si2Cl6 exhibited a higher deposition rate with lower reactant exposures as compared with the deposition by using SiH2Cl2, and exhibited good physical and electrical properties that were equivalent or superior to those of the film deposited by using SiH2Cl2.