The improvement of MOSFET performance by the optimization of STI HDP-CVD integration process

•Plasma charging damage on gate oxide is a key factor to degrade Vt performance.•H2 plasma produces low sputtering rate to reduce plasma charging damage.•The Vt performance has an inversely proportional relationship to sputtering rate.•Both NMOSFET and PMOSFET are improved by optimized HDP-CVD process.

The integration process of shallow trench isolation (STI) deposition was systematically investigated by using high-density plasma chemical vapor deposition (HDP-CVD). Two sputtering agents, Ar and H2, were utilized with various plasma RF power conditions. The STI HDP-CVD process consisted of two steps, including liner oxide and main gap-fill depositions. For the liner oxide deposition, the usage of Ar plasma was more favorable than H2 plasma because the drift of hydrogen-ions was detrimental for the electrical property of gate oxide. In the gap-fill process, H2 plasma with high bias RF power efficiently reduced plasma charging damage (PCD) on gate oxide due to its low sputtering rate and densely filled STI. The gap-fill capability and PCD were improved by the optimized condition of STI HDP-CVD process.

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