Synchrotron Topographic Studies of the Influence of Rapid Thermal Processing on Defect Structures in Single Crystal Sili
- PDF / 3,185,751 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 108 Downloads / 198 Views
SYNCHROTRON TOPOGRAPHIC STUDIES OF THE INFLUENCE OF RAPID THERMAL PROCESSING ON DEFECT STRUCTURES IN SINGLE CRYSTAL SILICON. MICHAEL DUDLEY-, FRANKLIN F.Y. WANG-, THOMAS FANNING-, GEORGIOS TOLIS*, JUN WU- AND DAVID T. HODUL**. *Dept. of Materials Science & Engineering, SUNY at Stony Brook, NY 11794; "**Varian Research Center, Varian Associates Inc., Palo Alto, CA 94303.
ABSTRACT. Synchrotron white beam X-ray diffraction topography in transmission geometry has been used to non-destructively investigate defect structures in silicon single crystal wafers, both prior and subsequent to a 60 second rapid thermal processing (RTP) treatment at 1050°C. Prior to RTP dislocations, precipitates and swirl defects were observed and characterized. Following RTP the following effects were observed: glide of individual dislocations and dislocation multiplication; and the enhancement of the strain field associated with the swirl defects. Precipitates appeared unaffected by RTP. This work shows that synchrotron topography is capable of non-destructively revealing significant dislocation motion induced by RTP under conditions were such motion is not thought to occur. This dislocation motion is likely to be detrimental to device performance. The technique enables determination of the conditions required to avoid such dislocation motion. INTRODUCTION. Mechanical damage potentially induced during rapid thermal processing (RTP) is an issue of central importance to the assessment of the general applicability of this annealing technique in the semiconductor industry. One of the pretexts for using RTP is that it induces fewer unwanted side effects than conventional annealing techniques, due to the much shorter time scales involved. However, despite much commercial interest, work devoted to the investigation of the microstructural side effects associated with this technique has been restricted either to electron and optical microscopic examinations [1], which by nature are restricted to low field of view or near surface studies, respectively, or to observations of the leakage currents associated with slip, using capacitors [2]. For example it is well known that for temperatures greater than 1200°C, radiative losses at the wafer perimeter may cause wafer bending and result in crystalline slip, readily visible through optical microscopy if proper countermeasures are not taken [3]. These countermeasures consist of utilizing specialized specimen mounts and heating rates designed to avoid excessive bending and thereby avoid the appearan~ce of slip lines on the crystal surface. To date, no systematic study has been made of the effect of RTP on the bulk internal microstructure. As will be clear from the topographs presented later, Transmission Electron Microscopy (TEM), with its small field of view, is not applicable in such studies due to the low defect densities involved both before and after RTP. The destructive nature of the technique is also not desirable if correlations between RTP induced damage and electronic device behavior are to be subse
Data Loading...
