The control and engineering of intrinsic point defects and impurities in silicon crystal growth and wafer processing

Prof. Dr. Robert Falster, MEMC Electronic Materials, Novara (Italy) and London (UK)

Silicon produced for the microelectronic industry is far and away the purest and most perfect crystalline material manufactured today.  It is done so routinely and in very large volumes.  Many of the advances in integrated circuit manufacturing achieved in recent years would not have been possible without parallel advances in silicon crystal quality and defect engineering.  Of particular importance has been the control and engineering of micro-defects and oxygen precipitation. This paper reviews some of the recent advances in the control and engineering of the intrinsic point defects which are centrally important to both classes of defect. Advances in the engineering of intrinsic point defects in both crystal growth and wafer processing has been central to a recent revolution in silicon defect engineering for advanced integrated circuit applications.  The installation of initial point defect concentration fields, their redistribution, relaxation, binding with impurities and subsequent reaction are covered.  The production of very large micro-defect free “perfect” crystals is discussed along with the creation of controlled vacancy concentration “templates” in thin silicon wafers in order to imprint robust, reproducible and ideal oxygen precipitation profiles for internal gettering applications.  Finally, much has been learned recently about the transport and binding of oxygen and nitrogen to dislocations with important implications for the mechanical properties of silicon wafers in practical processing situations.  Time permitting, this will also be briefly reviewed.