Carbon delta doping in chemical beam epitaxy using CBr4

We describe the growth of carbon δ-doped GaAs by chemical beam epitaxy (CBE) using CBr4 as the dopant during growth interrupts. Characterisation of the δ-doped samples using secondary ion mass spectrometry (SIMS) at a series of impact energies showed that the C was confined to a planar sheet less than 1 nm thick. This is in agreement with HRXRD measurements on C δ-doping superlattices. The results of SIMS profiling of layers with a range of interrupt times indicate that there is an initial surface coverage of C from CBr4 of approximately 9 × 1012cm−2 which increases relatively slowly during an extended interrupt.