| 摘要 |
A high resistivity monocrystalline N-type silicon layer is formed on a monocrystalline low resistivity antimony and/or bismuth doped N-type silicon substrate by deposition from a vapour phase consisting of thermally decomposable chlorine containing compounds of silicon and a donor impurity. In a typical method, 0.005 ohm cm. antimony doped N-type silicon wafers cut from a melt-grown monocrystal with their major surfaces lying in a 111, 100, 110, or 211 crystallographic plane, are mounted, after surface cleaning, in wells in heater element 12 (Fig. 1). After raising the wafers to 1170 DEG C. a turbulent flow of hydrogen is passed through the chamber 10 for 30 minutes to prepare the wafers for monocrystalline <PICT:1000731/C1/1> growth. Turbulence is produced by appropriate design of jet 19, by a mechanical stirrer, or by maintaining steep temperature gradients in the chamber. A mixture of phosphorus trichloride and silicochloroform is next introduced into the hydrogen flow for 5 minutes to form an 8 ohm cm. N-type layer 12m thick on the wafers. The wafers may be left in the chamber for a further 3 minutes with boron trichloride replacing the phosphorus trichloride to form a 10 ohm cm. P-type layer 2-3m thick. Alternative vapours from which to deposit silicon are silicon tetrachloride and silicon tetrabromide. |
