Predeposition in Silicon as Affected by the Formation of Orthorhombic SiP and Cubic SiO2 · P 2 O 5 at the PSG‐Si Interface

The phenomena limiting heavy phosphorus predeposition in silicon have been studied in the temperature range 850°–1000°C by using electrical measurements and x‐ray diffraction, together with optical and electron microscopy and Rutherford backscattering of He ions. It is reported that increasing the flux of dopant across the oxide layer, either by reducing oxygen pressure or by increasing that of , leads ultimately to anomalous doping kinetics associated to segregation of orthorhombic and cubic at the PSG‐Si interface, and to damage and loss of adhesion of the surface oxide. Increasing temperature acts in opposition to the onset of this phenomenon due to the increased competitivity of bulk silicon diffusivity. Segregation is sensitive to the orientation of the slice: the (111) being the most favorable, followed by the (110) and (100), respectively. The parameters leading to interface segregation are analyzed and discussed.