Crystal growth of boron monophosphide using a B 2H 6-PH 3-H 2 system

Abstract

Boron monosphide (BP) with (100) orientation can be epitaxially grown on Si substrates with (100) orientation by thermal decomposition of B 2H 6 and PH 3 in hydrogen. In a horizontal CVD system, the growth rate was studied as a function of gas phase composition and temperature. The growth rate is independent of the PH 3 partial pressure in the region where the PH 3 is in excess. For low values of the B 2H 6 partial pressure the growth rate is proportional to the B 2H 6 partial pressure (a linear region) with an activation energy of 1.8 eV, and for high values of the B 2H 6 partial pressure the growth rate becomes constant (a saturation region) with an acivation energy of 3.0 eV. A simple adsorption-reaction model can be proposed to explain the experimental growth kinetics. The conductivity of the as-grown layer is determined by the PH 3 partial pressure. n-type BP can be obtained for high values of the PH 3 partial pressure and p-type BP for low values. Si doping during the growth and phosphorus anti-site donors are two possibilities to explain the results.