AN OVERVIEW OF THE DEPOSITION CHEMISTRY AND THE PROPERTIES OF IN-SITU DOPED 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 silicon films in the semiconductor industry. However, as the trends towards lower temperatures, smaller dimensions and more complex geometries continue, it is becoming increasingly important to obtain a better fundamental understanding of the chemistry and properties of the layers deposited in order to achieve better control of the process. In this paper an overview is given of the chemistry, growth kinetics, electrical properties and structure of in situ doped polysilicon and of how these factors are related to reactor parameters. In addition, the effects of wafer cages on the within-wafer uniformity are discussed. Heat treatment using rapid thermal annealing has a significant impact on the electrical and structural properties of polysilicon and these effects are also examined.