MBE GROWTH AND CHARACTERIZATION OF IN-SITU ARSENIC DOPED HGCDTE

We report the results of in situ arsenic doping by molecular beam epit axy using an elemental arsenic source. Single Hg1-xCdxTe layers of x s imilar to 0.3 were grown at a lower growth temperature of 175 degrees C to increase the arsenic incorporation into the layers. Layers grown at 175 degrees C have shown typical etch pit densities of 2E6 with ach ievable densities as low as 7E4cm(-2). Void defect densities can routi nely be achieved at levels below 1000 cm(-2). Double crystal x-ray dif fraction rocking curves exhibit typical full width at half-maximum val ues of 23 arcsec indicating high structural quality. Arsenic incorpora tion into the HgCdTe layers was confirmed using secondary ion mass spe ctrometry. Isothermal annealing of HgCdTe:As layers at temperatures of either 436 or 300 degrees C results in activation of the arsenic at c oncentrations ranging from 2E16 to 2E18 cm(-3). Theoretical fits to va riable temperature Hall measurements indicate that layers are not comp ensated, with near 100% activation after isothermal anneals at 436 or 300 degrees C. Arsenic activation energies and 77K minority carrier li fetime measurements are consistent with published literature values. S IMS analyses of annealed arsenic doping profiles confirm a low arsenic diffusion coefficient.