Chemical vapor deposition of P-type and N-type semiconducting boron carbide thin films

Chemical vapor deposition of boron carbide produces films which are valued for their outstanding hardness, excellent mechanical, thermal and electrical properties. Many film polytypes can be produced, depending on the deposition conditions and the precursors. Some, but not all, of these CVD boron carbide films are semiconducting, a special property giving them micro-electronic applications ranging from low-powered neutron detectors for homeland security to direct power conversion devices. Here, growth parameters for a 13.56 MHz RF argon plasma reactor with both meta- and ortho-carborane precursors are investigated. Orthocarborane consistently produces p-type films, and metacarborane, n-type. Substrate temperatures are varied from 302 C to 321 C and mildly influence growth rates. Deposition times ranging from 10 to 420 minutes influence growth rates significantly. Metacarborane precurors grew at more than theoretically predicted 1.5 times faster than Orthocarborane precursors.