Material quality characterization of CdZnTe substrates for HgCdTe epitaxy

Jacobs

Markunas

et al. 2008

X-ray diffraction full-width at half-maximum (XRD FWHM), reflection highenergy electron diffraction (RHEED), and atomic force microscopy (AFM) indicate a mosaic structure for molecular-beam epitaxy (MBE) (211)B CdTe/Si. AFM measurements indicate long, thin, small-angle-disoriented grains for CdTe/Si epilayers. These disoriented grains are $1 lm in the [111] direction and are $40 nm in the [011] direction. The RHEED pattern in the [111] direction depicts nearly ideal single-crystal periodicity. The RHEED pattern in the [011] direction is indicative of small-angle-disoriented crystalline grains. Scanning electron microscopy (SEM), AFM, and XRD measurements all indicate an approximate factor of 10 increase in the Everson etch pit density (EPD) over standard Nomarski microscopy Everson EPD determination.

Section: Introductionmentioning

confidence: 99%

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

Jacobs

Markunas

et al. 2008

“…As-grown molecular beam epitaxy (MBE) (112)B CdTe/Si has a larger defect density and more disordered crystallinity than bulk (112)B CdZnTe substrates. [1][2][3][4][5][6][7][8][9][10][11] This results in MBE (112)B HgCdTe/ CdTe/Si having a larger defect density and more disordered crystallinity than MBE (112)B HgCdTe/ CdZnTe. MBE-deposited HgCdTe/Si devices are currently available.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Dislocations in (112)B HgCdTe/CdTe/Si

Bubulac

Smith

et al. 2010

Self Cite

The electrical performance of HgCdTe/Si photodiodes is shown not to have a direct relationship with the dislocation density as revealed by defect etching. This has led to an equivalent circuit model to explain the relationship of the dislocation density and the electrical test data. A new (112)B HgCdTe/CdTe/Si and CdTe/Si etch pit density (EPD) etch has been demonstrated. The new etch has been used to look for distinctive features which may be responsible for the poor electrical performance of individual diode pixels. The new etch chemistry also reduces the surface roughness of the etched epilayer and makes EPD determination less problematic. The new (to HgCdTe) technique of electrostatic force microscopy has also been used to analyze the electrical properties of dislocations.

“…As-grown molecular beam epitaxy (MBE) (112)B CdTe/Si has a larger defect density and more disordered crystallinity than bulk (112)B CdZnTe substrates (see Table I and Refs. [1][2][3][4][5][6][7][8][9][10][11]. This results in MBE (112)B HgCdTe/CdTe/Si having a larger defect density and more disordered crystallinity than MBE (112)B HgCdTe/CdZnTe (Table I).…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] The resulting higher dark current limits focal-plane array (FPA) operability. The goal of this effort is to examine the crystalline structure of MBE (112)B HgCdTe/CdTe/Si to determine possible areas for improvement.…”

Section: Introductionmentioning

confidence: 99%

Topography and Dislocations in (112)B HgCdTe/CdTe/Si

Smith

Jacobs

et al. 2009

Self Cite

Scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray diffraction (XRD) measurements all indicate an approximate factor of ten increase in the Everson etch pit density (EPD) over standard Nomarski microscopy Everson EPD determination. A new (112)B CdTe/Si EPD etch has also been demonstrated which reduces the surface roughness of the etched epilayer and makes etch pit density determination less problematic.