A comparison of C54-TiSi 2 formation in blanket and submicron gate structures using in situ x-ray diffraction during rap
- PDF / 584,277 Bytes
- 5 Pages / 576 x 792 pts Page_size
- 33 Downloads / 154 Views
G. Morales and K. F. Ludwig, Jr. Department of Physics, Boston University, Boston, Massachusetts 02215
G. Gifford IBM Microelectronics Division, Hopewell Junction, New York 12533
J. Bucchignano and J. Jordan-Sweet IBM Research Division, T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598
P. DeHaven IBM Microelectronics Division, Hopewell Junction, New York
G. B. Stephenson IBM Research Division, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (Received 9 December 1994; accepted 25 May 1995)
We demonstrate the use of a synchrotron radiation source for in situ x-ray diffraction analysis during rapid thermal annealing (RTA) of 0.35 fim Salicide (self-aligned silicide) and 0.4 /nm Polycide (silicided polysilicon) TiSi2 Complementary Metal Oxide Semiconductor (CMOS) gate structures. It is shown that the transformation from the C49 to C54 phase of TiSi2 occurs at higher temperatures in submicron gate structures than in unpatterned blanket films. In addition, the C54 that forms in submicron structures is (040) oriented, while the C54 that forms in unpatterned Salicide films is randomly oriented. Although the preferred oreintation of the initial C49 phase was different in the Salicide and Polycide gate structures, the final orientation of the C54 phase formed was the same. An incomplete conversion of C49 into C54-TiSi2 during the RTA of Polycide gate structures was observed and is attributed to the retarding effects of phosphorus on the transition.
I. INTRODUCTION Thin film silicides are extensively used for submicron complementary metal oxide semiconductor (CMOS) gate conductors in the semiconductor industry because they significantly reduce the resistance of CMOS gates compared to nonsilicided structures.1'2 TiSi2 has become one of the most widely used silicides for submicron gate conductor applications because of its low resistivity and good thermal stability.3 TiSi2 is a polymorphic material that forms the high resistivity C49 phase (60-70 /ill-cm) from a reaction between Ti and Si or the crystallization of amorphous-TiSi2 at temperatures less than about 700 °C and transforms into the low resistivity (15 to 20 {iQ,-cm) C54 structure at temperatures above approximately 700 °C. Since the high resistivity of C49 is unsuitable for high performance CMOS gate applications, the complete conversion of this phase into the low resistivity C54 phase during thermal annealing is critically important.1-2 There are J. Mater. Res., Vol. 10, No. 9, Sep 1995 http://journals.cambridge.org
Downloaded: 16 Mar 2015
two main types of silicide processes that are used to create submicron gate conductors: Salicide (self-aligned silicide) and Polycide (silicided polysilicon gates). In a Salicide process the gate conductor is formed by reacting titanium with exposed silicon gate structures to form a TiSi2 silicide gate contact. In contrast, in a Polycide process an amorphous titanium silicide is first deposited and then patterned to form the gate contact. A key technological challenge a
Data Loading...
