I n s i t u doping of Si and Si1−xGex in ultrahigh vacuum chemical vapor deposition

Abstract
We report on the growth of germanium–silicon and siliconepitaxial layers by ultrahigh vacuum/chemical vapor deposition. When an i n s i t u clean is used, filmsgrown at 600 °C are defect‐free by planar section transmission electron microscopy and no oxygen is detectable by secondary ion mass spectroscopy at the growth interface. I n s i t udoping has been studied using B2H6/H2 and PH3/H2 as source gases. Ge0.13Si0.87filmsdoped with boron up to 5×1019 cm−3 have been grown and sharp doping transitions have been obtained. Phosphorus doping concentrations in silicon are limited by a decrease in growth rate with increasing phosphorus flow rate which is attributed to phosphorus blocking of reaction sites. A model for the decrease in growth rate with PH3/H2flow is proposed which provides a good fit to the measurements.