Damage formation and annealing studies of low energy ion implants ...

Chapter 6 Annealing studies
6.1 Introduction
In this chapter the results of a range of annealing studies are described and
discussed, most of which were carried out within the IMPULSE project and as such are
highly relevant to current technologies and possible solutions for future devices. The
studies in this chapter fall into three general categories.
The first category in section 6.2 focuses on implantation and annealing
conditions that are similar to those used in device production. This is based on
annealing predominantly using RTA and spike annealing, at temperatures above
1000 °C. Comparisons with lower temperatures are also included. The effects of
reduced implant energy are discussed. The predominant feature with these conditions is
that diffusion of the dopant will be the limiting factor in reducing the junction depth.
The second category in this chapter is in section 6.3, concerning studies of SPER
at lower annealing temperatures, in the region of 550 °C to 700 °C. This annealing
range has been identified as a possible solution for 65 and 45 nm nodes, as the problem
of diffusion would be minimal (1-3). Note that in the semiconductor industry the
terminology SPER often refers to annealing at lower temperatures, approximately 550 –
800 °C. From a physical point of view, regrowth at higher temperatures still occurs by
the SPER process but is more commonly referred to as RTA/RTP, spike annealing,
flash etc, based on the annealing equipment used rather than the physical process that
occur.
The final category, in section 6.4, is the regrowth behaviour of SOI wafers,
which are currently being implemented in production. Differences in annealing
behaviour were observed in SOI compared to bulk Si.
One of the features of the IMPULSE project was to further develop analytical
techniques for USJ characterisation. Dispersed throughout this chapter are some of the
interesting comparisons with various X-ray techniques carried out at the ESRF. As well
as providing additional information on the samples, these highlight the potential of these
techniques for future studies.
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