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

Volume

13

Issue

4

fYear

2004

Firstpage

669

Lastpage

675

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 Si_xGe_1-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;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/JMEMS.2004.832189

Filename

1321105