Iodine and arsenic doping of (100)HgCdTe/GaAs grown by metalorganic vapor phase epitaxy using isopropyl iodide and tris-dimethylaminoarsenic

Abstract

We report in situ n- and p-type doping of HgCdTe/CdTe/(1 0 0)GaAs grown by metalorganic vapor phase epitaxy (MOVPE), using the interdiffused multilayer process (IMP). HgCdTe was doped either with iodine from isopropyliodide (IPI) for n-type doping or with arsenic from tris-dimethylaminoarsenic (DMAAs) for p-type doping. Standard bubbler configurations were used for dopant precursors. DiPTe, DmCd and elemental Hg were used as sources. HgCdTe layers of 10 mu m were grown on (1 0 0)GaAs at 370 degrees C. Dopant gases were allowed into the reactor only during the CdTe growth cycle of the IMP process. HgCdTe layers were Hg-annealed at 415 degrees C for 15 min and at 220 degrees C for 3 h, consecutively. Iodine-doped HgCdTe layers had 77 K electron concentrations of 6 x 10(15) to 5 x 10(17) cm(-3). Hall mobility decreased with increasing doping concentration. Arsenic-doped PgCdTe layers had 77 K hole concentration of 2 x 10(16) to 7 x 10(17) cm(-3) with about 100% of arsenic activated. Composition x of Hg1-xCdxTe layers was not influenced by the arsenic doping. The above results show that IPI and DMAAs precursors are excellent n- and p-doping sources for HgCdTe. (C) 1998 Elsevier Science B.V. All rights reserved.