Hot wire chemical vapor deposited boron carbide thin film/crystalline silicon diode for neutron detection application

Boron carbide films have been deposited on n-type crystalline silicon substrate by hot wire chemical vapor deposition technique using ortho-carborane precursor. The deposited films have been characterized by secondary ion mass spectrometry for their isotopic study which shows the presence of B-10 in the film making them suitable for thermal neutron absorber application. These films have a p-type semiconducting nature and hence can be employed to form a p-n junction with n-type silicon. We have demonstrated for the first time the formation of a p-n junction with films deposited by hot wire chemical vapor deposition technique. The current-voltage characteristics of the diode have been measured and the characteristics show low leakage current ((nA) under bar) in the reverse bias condition. From capacitance-voltage study, it is observed that the depletion width is of the order of few microns which is sufficient for detection of alpha particle released by B-10 in the n, alpha reaction. The results of this study indicate that hot wire chemical vapor deposited boron carbide/crystalline silicon diode could be used as a compact device for thermal neutron detection. (C) 2012 Elsevier Ltd. All rights reserved