Laser‐Assisted Chemical Vapor Deposition of Boron

Abstract

Abstract Ar + laser‐induced chemical vapor deposition (LCVD) of B from gaseous mixtures of BCl 3 and H 2 has been investigated for temperatures between 1000 K and 2250 K and for partial pressure within the ranges 25 mbar ≤ p(BCI 3 ) ≤ 800 mbar and 10 mbar ≤p(H 2 ) ≤ 400 mbar. For the lowest temperatures, deposition is controlled by the chemical kinetics which, with p(BCI 3 ) = p(H 2 ) = 100 mbar, is characterized by an apparent chemical activation energy of about 26.5 kcal/mol. In this regime, the deposited boron is amorphous. At high temperatures, deposition becomes limited by gas‐phase transport and polycrystalline boron with βrhombohedral structure is obtained.