HgCdTe growth on (552) oriented CdZnTe by metalorganic vapor phase epitaxy

We report the growth of HgCdTe on (552)B CdZnTe by metalorganic vapor phase epitaxy (MOVPE). The (552) plane is obtained by 180 degrees rotation of th e (211) plane about the [111] twist axis. Both are 19.47 degrees from (111) , but in opposite directions. HgCdTe grown on the (552)B-oriented CdZnTe ha s a growth rate similar to the (211)B, but the surface morphology is very d ifferent. The (552)B films exhibit no void defects, but do exhibit similar to 40 mum size hillocks at densities of 10-50 cm(-2). The hillocks, however , are significantly flatter and shorter than those observed on (100) metalo rganic vapor phase epitaxy (MOVPE) HgCdTe films. For a 12-14 mum thick film the height of the highest point on the hillock is less than 0.75 mum. No t winning was observed by back-reflection Laue x-ray diffraction for (552)B H gCdTe films and the x-ray double crystal rocking curve widths are comparabl e to those obtained on(211)B films grown side-by-side and with similar allo y composition. Etch pit density (EPD) measurements show EPD values in the r ange of (0.6-5) x 10(5) cm(-2), again very similar to those currently obser ved in (211)B MOVPE HgCdTe. The transport properties and ease of dopant inc orporation and activation are all comparable to those obtained in (211)B Hg CdTe. Mid-wave infrared (MWIR) photodiode detector arrays were fabricated o n (552)B HgCdTe films grown in the P-n-N device configuration (upper case d enotes layers with wider bandgaps). Radiometric characterization at T = 120 -160 K show that the detectors have classical spectral response with a cuto ff wavelength of 5.22 mum at 120 K, quantum efficiency similar to 78%, and diffusion current is the dominant dark current mechanism near zero bias vol tage. Overall, the results suggest that (552)B may be the preferred orienta tion for MOVPE growth of HgCdTe on CdZnTe to achieve improved operability i n focal plane arrays.