| 摘要 |
PURPOSE:To obtain an element capable of detecting a thermal neutron beam with high sensitivity by a method wherein a boron film is deposited on one face of a semiconductor substrate by a plasma CVD method using a gas of diborane containing <10>B, at the same time, boron is implanted into the substrate and a p-type doped layer is formed. CONSTITUTION:After formation of a surface protective film 24, an n-silicon substrate 21 where a window 20 is opened by etching is placed as a substrate body 7 on a lower-part electrode 12. Then, the inside of a vacuum container 2 is evacuated to be 1X10<-6>Torr or below; after that, a gas where B2H6 containing 94% or more of <10>B is diluted with hydrogen to 1000ppm is introduced from a bomb 42 into a container 2; 4Torr is kept; after that, a direct current of 550V is applied to electrodes 11, 12 from a power supply 6; a glow discharge is generated; a boron film 22 is applied to the semiconductor substrate 21. When B2H6 containing concentrated <10>B is used, a film formation speed is increased by 1.7 times; a concentration value of contained <10>B becomes 94/19.8 times as compared with the case of natural boron; it is possible to obtain the boron film 22 whose content of <10>B is higher by 94/19.8X1.7 times during an identical film formation duration.
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