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RBS study of effect of arsenic and phosphorus interfacial segregation upon the sintering of contacts between implanted polycrystalline silicon and aluminum:silicon(1%)

Conference ·
OSTI ID:5336303
The sintering behavior of the interface between Al:Si(1%) alloy and polycrystalline Si (poly-Si) was studied as a function of the poly-Si implantation dose by combining RBS, SEM, TEM, and x-ray microanalysis. Two different N-dopants were used: arsenic and phosphorus. The dopants were implanted in the poly-Si layer and thermal annealing was used to obtain dopant segregation towards the poly-Si interfaces. After sintering, two main effects were detected: (1) Al-Si eutectic phase precipitates and Si crystallites are formed at the interface. (2) The density of precipitates is a function of the implantation dose. For doses above 1 x 10/sup 15/ at./cm/sup 2/, segregated arsenic and phosphorus are found to completely inhibit this precipitation process, provided that the segregation peak of the dopant profile is preserved before metallization. Several conclusions can be drawn: for surface concentrations higher than 8 x 10/sup 19/ at./cm/sup 3/, arsenic and phosphorus inhibit the precipitation of the Al-Si eutectic phase, and thus inhibit interactions between the films at the interface. Moreover, argon gas, used for sputtering deposition of aluminum, segregated at the poly-Si/Al:Si(1%) interface and may also inhibit the metal-semiconductor interdiffusion.
Research Organization:
Louvain Univ., Louvain-la-Neuve (Belgium). Microelectronics Lab.
DOE Contract Number:
AC05-84OR21400
OSTI ID:
5336303
Report Number(s):
CONF-840760-21; ON: DE850163615
Country of Publication:
United States
Language:
English