Long-Range Lateral Dopant Diffusion in Tungsten Silicide Layers
- Resource Type
- Periodical
- Authors
- Liao, S.; Bain, M.; Baine, P.; McNeill, D. W.; Armstrong, B. M.; Gamble, H. S.
- Source
- IEEE Transactions on Semiconductor Manufacturing IEEE Trans. Semicond. Manufact. Semiconductor Manufacturing, IEEE Transactions on. 22(1):80-87 Feb, 2009
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Tungsten
Silicides
Schottky diodes
Annealing
Testing
Manufacturing
Silicon
Schottky barriers
Boron
Job shop scheduling
Diffusion processes
diodes
doping
tungsten compounds
- Language
- ISSN
- 0894-6507
1558-2345
Novel diode test structures have been manufactured to characterize long-range dopant diffusion in tungsten silicide layers. A tungsten silicide to p-type silicon contact has been characterized as a Schottky barrier rectifying contact with a silicide work function of 4.8 eV. Long-range diffusion of boron for an anneal at 900 $^\circ$ C for 30 min has been shown to alter this contact to become ohmic. Long-range diffusion of phosphorus with a similar anneal alters the contact to become a bipolar n-p diode. Bipolar diode action is demonstrated experimentally for anneal schedules of 30 min at 900 $^\circ$ C, indicating long-range diffusion of phosphorus ( ${\sim} {\hbox{38}}\ \mu$m). SIMS analysis shows dopant redistribution is adversely affected by segregation to the silicide/oxide interface. The concept of conduit diffusion has been demonstrated experimentally for application in advanced bipolar transistor technology.