AVS 53rd International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM-MoA

Paper EM-MoA8
High-Resolution Depth Profiling of Implanted As and Sb in Si(001) with Excess Vacancy Concentration

Monday, November 13, 2006, 4:20 pm, Room 2003

Session: Contacts, Interfaces and Defects in Semiconductors
Presenter: L.V. Goncharova, Rutgers University
Authors: M. Dalponte, Universidade Federal do Rio Grande do Sul, Brazil
H. Boudinov, Universidade Federal do Rio Grande do Sul, Brazil
L.V. Goncharova, Rutgers University
T. Feng, Rutgers University
T. Gustafsson, Rutgers University
E. Garfunkel, Rutgers University
Correspondent: Click to Email
Medium energy ion scattering (MEIS) was used to investigate the near-surface defect distribution and As and Sb redistribution in silicon substrates with excess vacancy concentration and separation by implantation of oxygen (SIMOX) substrates, and also the effects of post-implantation annealing. As and Sb are the preferred n-type dopant for Si due to their small depth penetration during implantation and low diffusivity during annealing. Also, Sb requires a lower thermal budget to achieve the desired junction parameters, compared to As. A 150 nm deep vacancy-rich layer was formed by O@sub 2@@super +@ or N@sub 2@@super +@ implantation at 240keV, using a dose of 2.5x10@super 16@cm@super -2@ at 400°C. As and Sb were then implanted at 20keV to a dose of 5x10@super 14@ cm@super -2@ at room temperature. Dopant segregation to the SiO@sub 2@/Si interface and some dopant loss was observed in all samples. Several effects related to the nature of the defects present in the sample as well as to the pre-implantation species were observed after longer annealing. The amount of dopant loss appears to be correlated with the structure of the defects. The highest dopant losses were observed in the N and O pre-implanted samples, where the vacancies had point defect character. In Si (no excess vacancies) and SIMOX (vacancies in the form of stable complexes) the dopant loss was much lower than in the N and O samples. Effects due to the different chemical nature of pre-implanted species were also observed. The N pre-implanted samples had the lowest segregated Sb percentage and uniform dopant distribution. The nitrogen accumulation at the SiO@sub 2@/Si interface appears to reduce dopant losses, compared to the O pre-implanted samples with the same vacancy structure. CNPq, CAPES, NSF and SRC/Sematech are gratefully acknowledged for their financial support.