Microstructure and interfacial states of silicon dioxide film grown by lowtemperature remote plasma enhanced chemical vapor deposition

The properties of SiO2 film and the Si/SiO2 interface formed by remote plas ma enhanced chemical vapor deposition with the addition of chlorine into Si H4-N2O have been investigated. With the chlorine addition, the deposition r ate increased at low deposition temperatures but at temperatures above 150 degrees C, it decreased because of the desorption of surface halide species . Chlorine at the Si/SiO2 interface prevented further subcutaneous oxidatio n and formed strong, terminal site Si-Cl bonds which reduced the interface state density. The substitution reaction of O and H with Cl in the bulk oxi de film leads to a disordered film structure and decreased hydrogen concent ration. The surface roughness increased and the refractive index decreased with increased Cl-2 addition. With chlorine addition of less than 6 vol %, the interface trap density (located at similar to E-upsilon + 0.3-0.4 eV) s ignificantly decreased down to the 1-3 X 10(11) eV cm(2) level at the Si mi dgap. At high chlorine partial pressure and temperature, the local interfac e trap density (located at similar to E-upsilon + 0.7-0.8 eV) increased due to increased structural disorder resulting from breakage of the Si-O bond. (C) 1999 American Institute of Physics. [S0021-8979(99)07714-2].