stop 312 terminates beam 302 u03b1 particles emitted from bpsg sample 550 000 hr as observed by the detector equ2 alpha flux 5 5 u00d7 10 8 u03b1 hr cm 2 a neutron flux of 3 6 u00d7 10 12 neutrons cm 2 hr therefore under the natural cosmic ray neutron flux of 0 02 sec u02dc 72 hr cm 2 equ3 this result is in close agreement with the theoretical calculation that indicated 0 031 u03b1 hr cm 2 for a bpsg film 11 000 u00e5 thick from the theoretical and experimental calculations it is clear that replacing regular boron with the 11 b isotope e g removing 10 b will have a very profound impact on reducing alpha flux in semiconductor devices or any other devices using 34 natural 34 boron compounds this work shows that by using 11 b in all processes that usually incorporate boron the alpha flux due to the 10 b n u03b1 7 li reaction induced by cosmic neutron flux can be eliminated this is especially crucial for charge sensitive circuit elements such as the memory cells of drams using separated or enriched 11 b in place of normal boron can reduce package level alpha flux by at least 1000 times the disclosed embodiment can be modified and varied while remaining within the scope of the following claims while the claimed invention has been explained in connection with the embodiment of a dram the claimed invention also finds utility in other electronic devices having charge sensitive circuit elements such as charge coupled devices ccds and static random access memories srams further while a.