Title :
Pulsed-laser annealing, a low-thermal-budget technique for eliminating stress gradient in poly-SiGe MEMS structures
Author :
Sedky, Sherif ; Howe, Roger T. ; King, Tsu-Jae
Author_Institution :
Phys. Dept., American Univ., Cairo, Egypt
Abstract :
In this paper, we demonstrate eliminating the stress gradient in polycrystalline silicon germanium films at temperatures compatible with standard CMOS (Al interconnects) backend processing. First, we study the effect of varying the germanium concentration from 40% to 90%, layer thickness, deposition pressure from 650 to 800 mtorr and deposition temperature from 400 to 450°C, on the mechanical properties of SiGe films. Then the effect of excimer laser annealing (248 nm, 38 ns, 780 mJ/cm2) on stress gradient is analyzed. It is demonstrated that stress gradient can be eliminated completely by depositing SixGe1-x(10%\n\n\t\t
Keywords :
CMOS integrated circuits; excimer lasers; internal stresses; laser beam annealing; micromechanical devices; pulsed laser deposition; silicon compounds; 400 to 450 C; 650 to 800 mtorr; Al interconnects; CMOS backend processing; MEMS applications; SiGe; deposition pressure; deposition temperature; excimer laser annealing; germanium concentration; grain microstructure; layer thickness; low-thermal-budget technique; polycrystalline silicon germanium films; pulsed-laser annealing; stress gradient; surface roughness; Annealing; CMOS process; Germanium silicon alloys; Mechanical factors; Micromechanical devices; Pulsed laser deposition; Semiconductor films; Silicon germanium; Stress; Temperature; MEMS postprocessing; pulsed-laser annealing; silicon germanium;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2004.832189
