Ways to quantitatively detect antiphase disorder in GaP films grown on Si(0 0 1) by transmission electron microscopy

Abstract

The monolithic integration of GaP-based optoelectronic devices on exact-oriented (0 0 1) silicon (Si) substrates requires a defect-free GaP nucleation layer on the Si substrate. Antiphase disorder is a defect that inevitably arises at the GaP–Si interface if mono-atomic steps at the Si surface cannot be avoided. Using dynamic beam intensity simulations in electron microscopy, the present paper depicts transmission electron microscopic (TEM) dark field imaging conditions to examine the crystal polarity and hence the antiphase disorder. The methods are refined in such a way that even thin TEM specimens as well as very small (<10 nm) antiphase domains can be imaged at low sample tilts. Using the described techniques, one is able to show that the GaP growth temperature and growth mode play an important role in initiating the self-annihilation of antiphase boundaries by making them kink from {1 1 0} towards the {1 1 1} crystal planes.