Residual Hydrogen in Polycrystalline Silicon Produced from Monosilane by Fluidized-Bed CVD Method

It has been pointed out that polycrystalline silicon particles produced from monosilane by the fluidized-bed CVD method contain residual hydrogen that causes disturbance of flow in a crucible in the CZ process. In the present work, the residual hydrogen was desorbed from produced Si particles by heat treatment. The activation energy for the hydrogen desorption was determined by the temperature-programmed desorption (TPD) technique. By FTIR, various types of Si-H bonds were found in the Si particles produced. The adsorbance area was decreased with increase in the desorbed hydrogen by TPD. From this relationship, the total amount of residual hydrogen was determined to be around 0.05% of the hydrogen contained in the reacted monosilane. The particle density of Si particles increased linearly almost up to the true density, with a decrease in the absorbance area of FTIR by the heat treatment.