Diffusion of gallium in silicon

Abstract

Neutron activation analysis and secondary ion mass spectrometry were used to measure gallium profiles resulting from the diffusion of Ga into intrinsic silicon. The diffusion of the impurity was measured between 700 and 1100 °C. The diffusion coefficient in this wide temperature range follows the expression D=0.005 exp[−(2.70/kT)] cm2 sec−1. The possible intervention of surface effects in the diffusion kinetics is discussed. An estimate of the enthalpy of association of Ga vacancy is deduced. The solid solubility of gallium in silicon was measured in the same range and at various concentrations of donors and acceptors.