Molecular beam epitaxy growth of high-quality arsenic-doped HgCdTe

Abstract

We have initiated a joint effort to better elucidate the fundamental mechanisms underlying As-doping in molecular beam epitaxy (MBE)-grown HgCdTe. We have greatly increased the As incorporation rate by using an As cracker cell. With a cracker temperature of 700°C, As incorporation as high as 4 ϫ 10 20 cm Ϫ3 has been achieved by using an As-reservoir temperature of only 175°C. This allows the growth of highly doped layers with high quality as measured by low dislocation density. Annealing experiments show higher As-activation efficiency with higher anneal temperatures for longer time and higher Hg overpressures. Data are presented for layers with a wide range of doping levels and for layer composition from 0.2 to 0.6.

Arsenic incorporation in MBE‐grown HgCdTe studied with the use of ion milling

“…Summarising the data obtained, we can observe that they are consistent with the tendency established earlier [6][7][8]. The efficiency of incorporation of electrically active arsenic into MBE MCT films increases at T cr >600 °C.…”

As Doping in (Hg,Cd)Te: An Alternative Point of View

“…The use of a cracker cell enabled comparison between As 4 and As 2 . 1 Although more arsenic was incorporated with As 2 , much of it could not be activated at concentrations above 10 18 atoms cm -3 even after the high-temperature anneal. Up to $10 18 cm -3 , 100% activation of the arsenic can be achieved by an anneal at 400°C to 500°C followed by a vacancy-filling anneal at 250°C, both under Hg saturated conditions.…”

“…1. Group I doping by substitution on the group II sites has not been widely considered because these are fast diffusers and hence not suitable for abrupt junction control.…”

Structural Analysis of CdTe Hetero-epitaxy on (211) Si

“…1 In Table I the best reported values of X-ray diffraction (XRD) full-width at half-maximum (FWHM) and etch pit density (EPD) from molecular-beam epitaxy (MBE) (211)B HgCdTe/CdZnTe, HgCdTe/CdTe/Si, CdZnTe, and CdTe/Si have been compiled. [2][3][4][5][6][7][8][9][10][11] As-grown MBE (211)B CdTe/Si has a larger defect density and more disordered crystallinity than bulk (211)B CdZnTe substrates. This results in MBE (211)B HgCdTe/CdTe/Si having a larger defect density and more disordered crystallinity than MBE (211)B HgCdTe/CdZnTe.…”