Silicon Nitride (Si3N4) sacrificial replacement gate were fabricated using the nitride cast method. The purpose of the Si3N4 cast was to develop a stand-in gate, which is then replaced by metal after source/drain formation. The technique was developed by using hot phosphoric acid etch (at 160 ° C) to form nitride cast. The phosphoric acid has nitride etch rate of about 4nm/min and good selectivity over oxide and good uniformity over silicon. A cross sectional analysis was done to view process steps.
Ullah, Elias Mohammad
"Fabrication and Characterization of Silicon Nitride Sacrificial replacement Gate Technology,"
Journal of the Microelectronic Engineering Conference: Vol. 12
, Article 12.
Available at: http://scholarworks.rit.edu/ritamec/vol12/iss1/12