Heteroepitaxy of HgCdTe (211)B on Ge substrates by molecular beam epitaxy for infrared detectors

Epitaxial growth of (211)B CdTe/HgCdTe has been achieved on two inch germanium (Ge) by molecular beam epitaxy (MBE). Germanium was chosen as an alternative substrate to circumvent the weaknesses of CdZnTe wafers. The ease of surface preparation makes Ge an attractive candidate among many other alternative substrates. Best MBE CdTe growth results were obtained on (211) Ge surfaces which were exposed to arsenic and zinc fluxes prior to the MBE growth. This surface preparation enabled CdTe growth with B-face crystallographic polarity necessary for the HgCdTe growth. This process was reproducible, and produced a smooth and mirror-like surface morphology. The best value of the {422} x-ray double diffraction full width at half maximum measured from the HgCdTe layer was 68 arc-s. We present the 486 point maps of FWHM statistical values obtained from CdTe/Ge and HgCdTe/CdTe/Ge. High resolution microscopy electron transmission and secondary ion mass spectroscopy characterization results are also presented in this paper. High-performance middle wavelength infrared HgCdTe 32-element photodiode linear arrays, using the standard LETI/LIR planar n-on-p ion implanted technology, were fabricated on CdTe/Ge substrates. At 78K, photodiodes exhibited very high R0A figure of merit higher than 106 Ωcm−2 for a cutoff wavelength of 4.8 µm. Excess low frequency noise was not observed below 150K.

[1]  D. Edwall,et al.  Improving material characteristics and reproducibility of MBE HgCdTe , 1997 .

[2]  Bonnie A. Baumgratz,et al.  Direct growth of CdZnTe/Si substrates for large-area HgCdTe infrared focal plane arrays , 1995 .

[3]  Majid Zandian,et al.  Molecular beam epitaxial HgCdTe material characteristics and device performance: Reproducibility status , 1995 .

[4]  Sivalingam Sivananthan,et al.  Heteroepitaxy of CdTe on Si substrates in view of infrared and x-ray detection , 1996, Photonics West.

[5]  E. Ligeon,et al.  Polarity determination in compound semiconductors by channeling: Application to heteroepitaxy , 1988 .

[6]  G L Destefanis.  HgCdTe infrared diode arrays , 1991 .

[7]  R. S. List.  Electrical effects of dislocations and other crystallographic defects in Hg0.78Cd0.22Te n-on-p photodiodes , 1993 .

[8]  J. G. Pasko,et al.  Infrared diodes fabricated with HgCdTe grown by molecular beam epitaxy on GaAs substrates , 1989 .

[9]  G. Destefanis,et al.  Large improvement in HgCdTe photovoltaic detector performances at LETI , 1993 .

[10]  H. Vydyanath.  Status of Te-rich and Hg-rich liquid phase epitaxial technologies for the growth of (Hg,Cd)Te alloys , 1995 .

[11]  H. F. Schaake,et al.  Etch pit characterization of CdTe and CdZnTe substrates for use in mercury cadmium telluride epitaxy , 1995 .

[12]  I. Bhat,et al.  Growth of (100) oriented CdTe on Si using Ge as a buffer layer , 1994 .

[13]  N. Dhar,et al.  Planar p-on-n HgCdTe heterostructure infrared photodiodes on Si substrates by molecular beam epitaxy , 1997 .

[14]  N. Dhar,et al.  Heteroepitaxy of CdTe on {211}Si substrates by molecular beam epitaxy , 1996 .

[15]  T. Ohshima,et al.  Preparation of CdTe thin films on Ge substrates by molecular beam epitaxy , 1985 .

[16]  Scott M. Johnson,et al.  MBE-grown HgCdTe heterojunction structures for IR FPAs , 1996, Photonics West.

[17]  I. M. Young,et al.  Molecular beam epitaxial growth of high structural perfection, heteroepitaxial CdTe films on InSb (001) , 1981 .

[18]  J. Reno,et al.  Relation between crystallographic orientation and the condensation coefficients of Hg, Cd, and Te during molecular-beam-epitaxial growth of Hg1−xCdxTe and CdTe , 1986 .

[19]  H. Temkin,et al.  Spontaneous emission factor in oxide confined vertical-cavity lasers , 1997 .

[20]  Rajesh D. Rajavel,et al.  Status of MBE technology for the flexible manufacturing of HgCdTe focal plane arrays , 1996 .

[21]  T. Myers,et al.  Growth of CdTe films on sapphire by molecular beam epitaxy , 1983 .