Growth of Group III Nitrides. A Review of Precursors and Techniques

Abstract

The AlGaInN quaternary alloy system is uniquely suited for numerous device applications because the bandgap can be varied from 1.9 to 6.2 eV by changing the alloy composition. Growth of epitaxial device-quality group III (Al, Ga, In) nitride films has been hindered by a lack of suitably lattice matched substrates, the large equilibrium dissociation pressure of N 2 from the nitrides at typical growth temperatures, and predeposition reactions in the commonly employed metal-organic chemical vapor (MOCVD) precursors. The most successful films have been grown at temperatures in excess of 900 °C by MOCVD. However, high growth temperatures may limit compatibility and incorporation of group III nitrides with existing fabrication technologies and devices. Attempts to lower deposition temperature include activated nitrogen sources and alternative precursors. This review will discuss improvement in film properties as a function of growth chemistry and will focus on MOCVD precursors used specifically for the growth of group III nitrides.

In-rich AlxIn1−xN grown by RF-sputtering on sapphire: from closely-packed columnar to high-surface quality compact layers

“…However, the growth of high-quality and single-phase AlInN remains challenging due to the large immiscibility gap of the alloy [9,10] and the large growth temperature difference between InN and AlN [11].…”

Absolute densities of N and excited N2 in a N2 plasma

“…3,4 Nitrogen plasmas contain atomic N, as well as electronically 5,6 and vibrationally excited N 2 that carry several electron volts of energy above the ground state. Any or all of these highly reactive species can affect the surface and, thus, the deposition chemistry.…”

Solid-state metathesis reactions under pressure: A rapid route to crystalline gallium nitride

“…Other recent synthetic methods use polymeric and single-source precursors, microwave heating, and plasma assisted nitridation. [9][10][11][12][13] Single crystals of GaN are generally grown under high temperature ͑1700-1800 K͒/ high pressure conditions ͑Ͼ2 GPa for ϳ20 h͒ since GaN decomposes at ϳ1150 K under ambient pressure. [14][15][16] Recent experiments indicate sodium fluxes can be useful for crystal growth.…”