Iodine and arsenic doping of (1 0 0)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 μm were grown on (1 0 0)GaAs at 370°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°C for 15 min and at 220°C for 3 h, consecutively. Iodine-doped HgCdTe layers had 77 K electron concentrations of 6 × 10 15 to 5 × 10 17 cm −3. Hall mobility decreased with increasing doping concentration. Arsenic-doped HgCdTe layers had 77 K hole concentration of 2 × 10 16 to 7 × 10 17 cm −3 with about 100% of arsenic activated. Composition x of Hg 1− x Cd x Te 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.