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PHOSPHORUS GLASS DOPING OF POLYCRYSTALLINE SILICON DURING RAPID THERMAL ANNEALING BOUCHAIB HARTITI, ABDELILAH SLAOUI, ROLAND STUCK, JEAN-CLAUDE MULLER and PAUL SIFFERT Centre de Recherches Nucl~aires (IN2P3), Laboratoire PHASE (UPR du CNRS n-292), BP 20, F-67037 Strasbourg Cedex 2, France ABSTRACT We show that the use of phosphorus doped spin-on glasses as diffusion source is an attractive approach for the formation of shallow junctions in polycrystalline silicon materials. Moreover, this very simple doping process using a glass film can be fruitfully associated to rapid thermal annealing. INTRODUCTION In the semiconductor industry and especially* in integrated circuit (IC) technology, the requirements for scaling down of devices have become very important. The formation of very shallow junctions in silicon is one of the most important steps in meeting these requirements. Because of various problems associated to ion implantation and subsequent annealing [1], thermal diffusion of dopants into the silicon substrate from a solid, liquid or gaseous source has been widely investigated. Among these techniques, the use of phosphorus or boron doped spin-on glass (SOG) films as a diffusion source seems to be an attractive approach for the formation of shallow junctions. Indeed, coating with glass films is a very simple process and causes no damage. However, despite its growing success as surface passivation or capping layer [2], SOG films are until now only little used as a doping source [3-6]. On the other hand, rapid thermal annealing (RTA) using radiation from tungsten halogen lamps as a heat source has been seen as a very promising candidate to replace conventional furnace annealing. The RTA is probably better adapted to the fabrication of micron and submicron ICs than the other investigated alternative methods such as lasers, electron beams, resistance heaters and ion beam annealing technologies [7, 8]. Dopant diffusion from a doped oxide film or a solid dopant source using RTA seems to be an interesting alternative to avoid problems due to implantation damage. Recently, the use of RTA for doping from doped glass films [9,10] has been reported. However, no significant studies have concerned the bulk properties. In this study, we describe the diffusion of phosphorus into silicon from phosphorus-doped spin-on glass (SOG) films using RTA. Hereafter, we use the term rapid thermal diffusion for this process. The resulting diffused samples were characterized by measuring sheet resistance, dopant concentration profiles and minority carrier diffusion length in the bulk. EXPERIMNTAL PROCEDURE The study was carried out on 1 Q.cm p-type polycrystalline silicon wafers. The front side of this material was mirror polished and the back etched. Prior to processing, the samples were cleaned in 10 % HF. For the deposition of the SOG film, we used highly purified Emulsitone Co. (USA) sources. The samples were coated, by using the spin-on technique, with a 2000 3A a high phosphorus concentration (1 x 1021 P/cm) thick doped layer containi