Title :
Impact of Al melting on diode integrity
Author :
Kamgar, Avid ; Knoell, R.V. ; Baiocchi, F.A. ; Orlowsky, K.J. ; Cheung, K.P. ; Liu, R.
Author_Institution :
AT&T Bell Lab., Murray Hill, NJ, USA
Abstract :
The integrity of Al/barrier/CoSi2 junctions subjected to Al melting was studied. Melting was accomplished by irradiating Si wafers in a rapid thermal anneal system. Three types of barrier were studied: TiN, W:Ti, and a bilayer of W:Ti/TiN. Junction leakage measurements indicated that the W:Ti/TiN bilayer was superior to the other two and that it withstood temperatures at least 60°C higher than the Al melting temperature for one second or less. Rutherford backscattering, X-ray diffraction, and etchback experiments were performed to determine the extent of interaction between the various layers after the melt. The authors found that for the W:Ti barrier, upon melting of Al, W reacted readily with Al and Si, forming the ternary alloy, W(Al,Si)2, and possibly other phases including Co as a constituent. TiN on the other hand effectively prevented the reaction of Al and W with Co and Si
Keywords :
Rutherford backscattering; X-ray diffraction examination of materials; aluminium; chemical interdiffusion; cobalt compounds; incoherent light annealing; leakage currents; melting; metallisation; sputter etching; surface chemistry; titanium alloys; titanium compounds; tungsten alloys; Al melting; Al-CoSi2; Al/barrier/CoSi2 junctions; Rutherford backscattering; Si wafers; W(AlSi)2; WTi-TiN; X-ray diffraction; diode integrity; etchback; junction leakage; rapid thermal anneal system; Aluminum alloys; Backscatter; Cobalt alloys; Diodes; Etching; Rapid thermal annealing; Silicon alloys; Temperature; Tin; X-ray diffraction;
Conference_Titel :
VLSI Multilevel Interconnection Conference, 1989. Proceedings., Sixth International IEEE
Conference_Location :
Santa Clara, CA
DOI :
10.1109/VMIC.1989.78022
