We report on the metalorganic chemical vapor deposition of the quaternary a
lloy AlInGaN. We found it desirable to grow quaternary films at temperature
s greater than 855 degrees C in order to suppress deep level emissions in t
he room-temperature photoluminescence. Details of the conditions necessary
to grow In0.1Ga0.9N at 875 degrees C are presented. Strained and relaxed Al
InGaN films were grown with good optical and structural properties for AlN
compositions up to 26% and InN content up to 11%. The effects of strain wer
e observed by a difference in the band gap between thin and thick films wit
h the same compositions. The potential impact of the use of quaternary film
s is discussed regarding strain engineering for the improvement of present
device designs. (C) 1999 American Institute of Physics. [S0003-6951(99)0464
7-1].