STRESS CANCELLATION IN SILICON OXYNITRIDE INP STRUCTURES OBTAINED BY RAPID THERMAL CHEMICAL VAPOR-DEPOSITION

Rapid thermal chemical vapor deposition was utilized to deposit silicon-based dielectrics on III-V materials at high temperature. Silicon oxynitride films can be deposited on InP at 750-degrees-C with compositions varying between silicon dioxide and silicon nitride. Secondary ion mass spectroscopy and nuclear reaction analysis measurements show that the oxygen concentration in the layers varies continuously with the oxidant gas flow rate. The overall stoichiometry of the films can be controlled with this parameter. The composition of the layers has a direct incidence on the mechanical tension of the insulator/semiconductor structures. A highly sensitive optical setup has been developed to measure the tension on these samples in order to determine the stoichiometry of the silicon oxynitride (SiO(x)N(y)) film that leaves the structure unstressed. The stress-free film composition is shown to depend also strongly on the thickness of the layer. A study of the overall stress introduced in a structure during its fabrication is presented.