Growth of InP using TBP and DTBP in metalorganic molecular beam epitaxy

Abstract

The growth of high purity InP layers using trimethylindium (TMIn) and different commercial tertiarybutylphosphine (TBP) batches as well as ditertiarybutylphosphine (DTBP) as a new phosphorous precursor was studied in a production type metalorganic molecular beam epitaxy (MOMBE) growth chamber. The cracking behaviour of TBP was investigated by mass spectrometry. Increasing the beam equivalent pressure from 10 −6 Torr to growth relevant pressures in the 10 −5 Torr range, a transition of the pyrolysis regime was observed, accompanied with a reduced H 2+P 2 production and a strong formation of the hydride PH 3 and dihydride P 2H 4. This behaviour depends on the conditions on the cracker surface and indicates that the decomposition of TBP occurs by a radical formation process. At 77 K the deposited InP layers exhibited Hall mobilities better than 100 000 cm 2/V s for the use of three TBP batches from two different suppliers with a best value of 167 000 cm 2/V s at n=1.4×10 14 cm −3. The linewidth of the donor bound exciton in the 1.8 K photoluminescence spectrum of the sample with the highest electron mobility was about 0.09 meV. The first use of DTBP in MOMBE for the growth of high purity InP was also encouraging. The best value of the Hall mobility at 77 K was 77 300 cm 2/V s with n=5.1×10 14 cm −3.