Synthesis of Low Stress Silicon Nitride Thin Films at 80℃ by Inductively Coupled Plasma Chemical Deposition

The low stress silicon nitride thin films were synthesized at a temperature below 80℃ by inductively coupled plasma chemical vapor deposition(ICP-CVD).The influence of the synthesis conditions,including the pressure,deposition temperature,ICP power and ratio of SiH₄/N₂ flow-rates,on the stress distribution of silicon nitride thin films was investigated.The results show that the growth conditions all had a major impact.For example,as the flow rate ratio increased,the stress changed in a decrease-increase mode.Under the optimized deposition conditions,the silicon nitride dielectric thin films were grown at 70℃ with a stress of 0.03 MPa and a thickness of 160 nm.The possible mechanism(s) responsible for the influence of a specific growth condition on the stress were tentatively discussed in a thought provoking way.