AVS 45th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM1-WeA

Paper EM1-WeA9
The Initial Stages of Si(100) Oxynitridation by NO: An Infrared Study

Wednesday, November 4, 1998, 4:40 pm, Room 314/315

Session: Si Surface Chemistry
Presenter: J. Eng, Jr., Bell Laboratories, Lucent Technologies
Authors: J. Eng, Jr., Bell Laboratories, Lucent Technologies
K.T. Queeney, Bell Laboratories, Lucent Technologies
Y.J. Chabal, Bell Laboratories, Lucent Technologies
B.B. Stefanov, Bell Laboratories, Lucent Technologies
K. Raghavachari, Bell Laboratories, Lucent Technologies
X. Zhang, Rutgers University
E. Garfunkel, Rutgers University
Correspondent: Click to Email
The oxynitridation of Si(100) by N@sub 2@O has been studied extensively because the electrical properties of thin silicon oxynitride films are superior to those of silicon oxide films with the same thickness. Although the oxynitridation mechanism is not completely understood, it is generally believed that N@sub 2@O decomposes to form NO under industrial processing conditions, and that NO is the species ultimately responsible for oxynitridation. On this basis, we have chosen to study the initial reaction of NO with clean Si(100) by using infrared spectroscopy, Auger electron spectroscopy, and low energy electron diffraction. We conclusively show that NO dissociatively adsorbs on Si(100) at room temperature, thereby resolving an existing debate in the literature.@footnote 1@ Heating the NO/Si(100) surface to 650 @degree@C causes the formation of SiO@sub x@N@sub y@ structures which have strong characteristic modes at 858, 989, and 1057 cm@super -1@. These modes have been assigned based on isotopic labeling studies involving @super 15@N@super 16@O and @super 14@N@super 18@O, as well as ab-initio density functional calculations. Auger studies show that heating to 850 @degree@C removes oxygen, but the nitrogen 379 eV KLL feature is not attenuated. However, the Si-H vibrational features observed in H atom post-dosing experiments designed to probe the surface after heating to 850 @degree@C are similar to those obtained by exposing clean Si(100) to H atoms, indicating that the N atoms reside in subsurface sites. Additional information about the Si-N modes is obtained by studying the adsorption and thermal decomposition of ammonia on Si(100) surfaces. @FootnoteText@ @footnote 1@ Y. Taguchi, M. Fujisawa, and M. Nishijima, Surf. Sci. Lett., 233 (1990) L251-252