In-situ low energy BF2+ion doping for silicon molecular beam epitaxy

An experimental study of the p-type ion dopant BF
2
+ in silicon molecular beam epitaxy (MBE) is described. BF
2
+ was used to dope MBE layers during growth to levels ranging from 1 × 10
¹⁶
/cm
³
to 4 × 10
¹⁸
/cm
³
over a growth temperature range of 650°C to 1000°C. The layers were evaluated using spreading resistance, chemical etching, and secondary ion mass spectroscopy. Complete dopant activation was observed for all growth temperatures. Remnant fluorine in the epitaxial layer was less than 2 × 10
¹⁶
/cm
³
in all cases. Diffused p-n junction diodes fabricated in BF
2
+-doped epitaxial material showed hard reverse breakdown characteristics.