Rapid thermal processing in semiconductor technology

Abstract

We give a broad overview of some of the possible (and actual) applications of rapid thermal processing (RTP) techniques. Pioneering work done in the field of RTP is described, and a large number of references (about 90) are given. Because of the very wide range of possible applications the detail in which each is discussed may not be in direct relation to their importance for commercial or research purposes.The three main modes of RTP, the adiabatic, thermal flux and isothermal modes are described and contrasted in terms of heat flow, physical processes and suitability for various applications in the field of silicon semiconductor processing.The main types of equipment utilised for RTP research studies are briefly described, ranging from pulsed and cw laser and electron beam sources to radiant heat sources such as graphite plate and lamp systems.Three examples of the application of RTP to silicon semiconductor processing are described in some detail, with comparisons to conventional processing techniques made where relevant.The use of isothermal annealing systems for the acitivation of ion-implanted dopants is described and reviewed. The possible advantages of RTP are given, and the place of such technology in modern CMOS processing are briefly summarised.The formation of silicon-on-insulator structures using RTP techniques is described and compared with the competing technologies of oxygen implantation and porous silicon.Finally, the wide-ranging, new field of in situ multi-stage processing (or limited reaction processing) is briefly described, and possible applications discussed. This final section covers a subject in which much interest at the research level is presently focused.

Intense Pulsed Light Sintering of Electrodeposited CdS Thin Films

“…Conventional sintering processes rely on a furnace or hot plate to heat the material. Although the heating and cooling rates can be controlled, the time scales are typically in the tens of minutes . This dumps unnecessary energy in to the surroundings and the processing temperatures often limit the selection of substrates and capital equipment.…”

“…A tactic for combating these problems is to exploit rapid thermal annealing techniques. These methods can still allow the materials to be processed at a high temperature but are so fast that vacuum/inert atmospheres are not always necessary . Rapid thermal annealing encompasses a variety of techniques that fall in to the heat balance/isothermal, thermal flux or adiabatic thermal processing regimes .…”

Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion

“…An alternative annealing technique is rapid thermal processing (RTP), where these issues are much less prominent17. In RTP, an array of lamps is used to generate heat18, and the emitting power of the lamps delivers high temperature accuracy at the specimen. Ramp-up rates are normally of the order of 10 °C s −1 , but can also be as high as 400 °C s −1 .…”

An Ion Assisted Evaporation Technique for Use in the Fabrication of Semiconductor Devices

“…Therefore, the ion assisted evaporation technique used with RTA would be particularly suited to creating highly doped shallow layers [9], allowing the Schottky barrier height to be modified, thus improving device performance.…”