AN OVERVIEW OF THE DEPOSITION CHEMISTRY AND THE PROPERTIES OF IN-SITUDOPED POLYSILICON PREPARED BY LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITION

Low pressure chemical vapour deposition (LPCVD) has become the sta nda rd method for the fabrication of amorphous and polycrystalline silico n films in the semiconductor industry. However, as the trends towards lower temperatures, smaller dimensions and more complex geometries con tinue, it is becoming increasingly important to obtain a better fundam ental understanding of the chemistry and properties of the layers depo sited in order to achieve better control of the process. In this paper an overview is given of the chemistry, growth kinetics, electrical pr operties and structure of in situ doped polysilicon and of how these f actors are related to reactor parameters. In addition, the effects of wafer cages on the within-wafer uniformity are discussed. Heat treatme nt using rapid thermal annealing has a significant impact on the elect rical and structural properties of polysilicon and these effects are a lso examined.