Stress engineering during metalorganic chemical vapor deposition of AlGaN/GaN distributed Bragg reflectors

In situ stress monitoring has been employed during metalorganic chemical va por deposition of AlGaN/GaN distributed Bragg reflectors (DBRs). It was fou nd that the insertion of multiple AlN interlayers is effective in convertin g the tensile growth stress typically observed in this system into compress ion, thus alleviating the problem of crack generation. Crack-free growth of a 60 pair Al0.20Ga0.80N/GaN quarter-wavelength DBR was obtained over the e ntire 2 in. wafer; an accompanying reflectivity of at least 99% was observe d near the peak wavelength around 380 nm. (C) 2001 American Institute of Ph ysics.