No abstract

Amorphous and polycrystalline boron nitride (BN) films were deposited on n‐type Si substrates using a B2H6‐NH3‐H2 system. During deposition of the BN film, boron diffuses into the Si; a BN film deposited at temperatures below about 1000°C acts as an infinite diffusion source of boron in Si. The maximum values of boron surface concentration give solid solubility of boron in Si at each temperature. A thin layer of BN (below 80Å) gives a surface concentration of boron in the range between 1016 and 1020 cm−3, by varying the heat‐treatment conditions. Amorphous BN decomposes easily when heated in a nitrogen atmosphere. This can be used for planar diode processes using only one photomask. An MIS‐memory diode with normalAl‐BN‐SiO2‐normalSi structure, shows an anomalous C‐V shift due to the formation of borosilicate glass between BN and SiO2 .

Boron monophosphide (BP) was epitaxially grown on Si substrates with (100), (110) and (111) faces, by thermal decomposition of a B2H6-PH3 mixture in hydrogen in the temperature range of 950°C to 1050°C. The crystallographic orientation of the BP was the same as that of the Si substrates. n- and p-type BP were obtained under different growth conditions. The carrier concentrations without any additional doping were from 1018 to 1021 cm-3 and their mobilities were from 150 to 80 cm2/Vsec.

The low frequency dielectric constant of PbTe was determined by measuring the barrier capacitances of PbTe abrupt junctions at about 100 kc/s and low temperatures. The junctions were made by alloying In to p-type base crystals or Ag-Te alloy to n-type crystals. The donor or acceptor density in crystals was controlled by heat treatment to range from 1.5×1017 to 8.0×1018 cm-3. As the low frequency dielectric constant of PbTe a value of 400 was obtained, which is approximately constant in the temperature range from 4.2 to 130°K and in the frequency range from 10 to 150 kc/s. This high value of dielectric constant is sufficient to explain the large value of carrier mobility in PbTe at low temperatures.

Single crystal of lower boron phosphide (B13P2) with hexagonal structure was obtained hetero-epitaxially on silicon substrate. Diborane (B2H6) and phosphine (PH3) diluted in hydrogen were used as reactant gases. The substrate temperatures were between 1050°C and 1250°C and the molecular ratio of reactants to carrier hydrogen was below 3.2×10-4. The epitaxial relations were: B13P2(112̄0)/Si(100), B13P2(112̄0)/Si(110) and B13P2(101̄0)/Si(111). The lower boron phosphide was a transparent film and its resistivity was measured as 1×108 Ω-cm at room temperature.