Title :
Suppression of cobalt silicide agglomeration using nitrogen (N/sub 2//sup +/) implantation
Author :
Sun, Wein-Town ; Liaw, Ming-Chi ; Hsu, Charles Ching-Hsiang
Author_Institution :
Microelectron. Lab., Nat. Tsing Hua Univ., Hsinchu, Taiwan
fDate :
5/1/1998 12:00:00 AM
Abstract :
In this paper, the effects of nitrogen coimplantation with boron into p/sup +/-poly gate in PMOSFETs on the agglomeration effects of CoSi/sub 2/ are studied. The thermal stability of CoSi/sub 2//poly-Si stacked layers can be significantly improved by using nitrogen implantation. Samples with 40-nm cobalt silicide (CoSi/sub 2/) on 210-nm poly-Si implanted by 2/spl times/10/sup 15//cm/sup 2/ N/sub 2//sup +/ are thermally stable above 950/spl deg/C for 30 s in N/sub 2/ ambient. If the dose of nitrogen is increased up to 6/spl times/10/sup 15//cm/sup 2/, the sheet resistance of CoSi/sub 2/ film is not increased at all, and TEM photographs show that the agglomeration of CoSi/sub 2/ film is completely suppressed.
Keywords :
MOSFET; boron; cobalt compounds; elemental semiconductors; ion implantation; nitrogen; semiconductor device metallisation; silicon; thermal stability; 210 nm; 30 s; 40 nm; 950 degC; CoSi/sub 2/-Si:B,N/sub 2/; PMOSFET; TEM; coimplantation; p/sup +/-poly gate; sheet resistance; silicide agglomeration; thermal stability; Boron; Cobalt; Conductivity; MOSFET circuits; Nitrogen; Rapid thermal annealing; Silicides; Sun; Thermal degradation; Thermal stability;
Journal_Title :
Electron Device Letters, IEEE
