Plasma CVD-Grown ¹⁰B-Enriched Boron Films for Si Neutron Detectors

Hydrogenated amorphous boron (a-B:H) films were deposited on Si crystal substrates using DC glow discharge in B 2 H 6 diluted to 1000 ppm in H 2 . We found that the rate of the deposition was about two times higher for 10 B-enriched B 2 H 6 than for natural B 2 H 6 . The deposition process was observed by optical emission spectroscopy of the DC glow. BH emission lines at 433.2 nm and 369.4 nm were strongly enhanced in the 10 B-enriched B 2 H 6 /H 2 compared with the natural B 2 H 6 /H 2 . This manifests an isotopic effect on the deposition rate of the a-B:H film. Concentrations of 10 B, 11 B and 1 H in the films were analyzed by SIMS. The hydrogen content of the films was found to be 3.9 × 10 23 atoms/cm 3 from the thermal hydrogen release measured by gas chromatography. The 10 B-enriched film was applied to construct a novel silicon neutron detector. It showed a satisfactory sensitivity for neutron detection.