Effect of pretreatment of the silicon substrate on the properties of GaN films grown by chloride–hydride vapor-phase epitaxy

In this work, we report on the HVPE growth of a GaN film on pretreated Si (001) silicon substrates through an AlN buffer layer. We demonstrated that the use of the proposed technology led to the formation of a transitional sublayer $\sim$170–200 nm thick in the Si substrate, further growth on which provided the formation of columnar GaN grains between which there is a thin layer of the AlN phase. The GaN epitaxial film has a low residual stress, which is reflected in the intense luminescence.