The immiscibility of InAlN ternary alloy

Abstract

We have used two models based on the valence force field and the regular solution model to study the immiscibility of InAlN ternary alloy, and have got the spinodal and binodal curves of InAlN. Analyzing the spinodal decomposition curves, we obtain the appropriate concentration region for the epitaxial growth of the InN-AlN pseudobinary alloy. At a temperature most common for the epitaxial growth of InAlN (1000 K), the solubility of InN is about 10%. Then we introduce the mismatch strain item into the Gibbs free energy, and the effect of different substrates is taken into consideration. Considering Si, Al2O3, InN, GaN, AlN as a substrate respectively, it is found that all the five systems are stabilized with the upper critical solution temperature largely reduced. Finally, InN and GaN are potential substrates for In-rich InAlN, while AlN and GaN substrates are recommended in the Al-rich region. Si and Al2O3 may be ideal substrates for thin InAlN film.

Investigation of strain effects on phase diagrams in the ternary nitride alloys (InAlN, AlGaN, InGaN)

“…When the compressive strain is brought to 2%, T c increases abruptly to reach 3336 K. In contrast, applying a tensile stress of 2% still decreases the critical temperature T c that reaches 925 K. Therefore, whichever the direction of increase in strain (increase or decrease in indium concentration), below 1.5% for the growth of InAlN for instance on GaN, the unstable region is significantly reduced with a T c that can be as low as 586 K. This work is in agreement with the results reported in reference which studied the InAlN/GaN alloys and pointed out possible phase separation at indium rich composition ranges where the compressive strain is also highest. We also agree with the recent calculations of Zhao et al who reported that knowing the lattice mismatch may help in a search for the most adequate substrates for the InAlN alloy; most importantly, our results show that one should stay at small compressive strains.…”

Tuning the piezoelectric and mechanical properties of the AlN system via alloying with YN and BN

“…However, the current growth techniques (e.g. reactive dc magnetron co-sputtering) [24][25][26] rely on non-equilibrium processes to overcome the solubility limits [27][28][29] and create alloys with better control over properties through control of composition.…”

Direct observation of spinodal decomposition phenomena in InAlN alloys during in-situ STEM heating

“…In parallel, observations by electron microscopy revealed In-rich dot-like features in InGaN quantum wells456, which are thought to result from spinodal decomposition. Similarly, for InAlN there exists a large miscibility gap though AlGaN is not expected to decompose278. Spinodal decomposition is a common and technically beneficial process9 for a number of metals and ceramics1011 such as TiAlN.…”