Direct growth of high-quality CdTe epilayers on Si(211) substrates by metalorganic vapor-phase epitaxy

High-quality (211)B CdTe buffer layers are required during Hg 1Àx Cd x Te heteroepitaxy on Si substrates. In this study, direct metalorganic vapor-phase epitaxy (MOVPE) of (211)B CdTe on Si, as well as CdTe on Si using intermediate Ge and ZnTe layers, has been achieved. Tertiary butyl arsine was used as a precursor to enable As surfactant action during CdTe MOVPE on Si. The grown CdTe/Si films display a best x-ray diffraction rocking-curve fullwidth at half-maximum of 64 arc-s and a best Everson etch pit density of 3 9 10 5 cm À2 . These values are the best reported for MOVPE-grown (211)B CdTe/Si and match state-of-the-art material grown using molecular-beam epitaxy.

Section: Resultsmentioning

confidence: 99%

High-Quality (211)B CdTe on (211)Si Substrates Using Metalorganic Vapor-Phase Epitaxy

Rao

Shintri

Markunas

et al. 2011

“…Details on the growth of high-quality single-crystal CdTe epitaxial layers on (211) Si substrates have been reported elsewhere. 1,6 The growth was carried out at substrate temperatures of 325°C to 560°C, using dimethylcadmium (DMCd) and diethyltellurium (DETe) as group II and group VI precursors, respectively. Ethyl-iodide (EI), ethyl-chloride (EC), and trichloromethane (TCM) were used as dopants.…”

Section: Methodsmentioning

confidence: 99%

“…[1][2][3][4] We have previously reported on metalorganic vaporphase epitaxy (MOVPE) growth of thick singlecrystal CdTe layers (100 lm to 260 lm) on Si as well as on GaAs substrates and the development of gamma-ray detectors using these epilayers. 1,[4][5][6] The detectors were fabricated in a p-CdTe/n-CdTe/n + -Si heterojunction diode structure, where the p-CdTe and the n-CdTe layers were typically 100 lm and 5 lm thick, respectively. 5 The detectors were capable of detecting gamma radiation and measuring its energy distribution, when operated in pulse mode by applying a reverse bias voltage.…”

Section: Introductionmentioning

confidence: 99%

Electrical Properties of Halogen-Doped CdTe Layers on Si Substrates Grown by Metalorganic Vapor-Phase Epitaxy

Yasuda

Niraula

Oka

et al. 2010

Self Cite

Electrical properties of halogen-doped CdTe layers grown on Si substrates using iodine and chlorine dopants are presented. No change in electrical properties of the layers was observed with chlorine as a dopant. However, doping with iodine resulted in highly conductive n-type layers or highly resistive p-type layers depending upon the growth conditions, even though a similar amount of dopant was introduced into the growth chamber. Layers grown at 560°C, with a vapor-phase Te/Cd precursor ratio of 3.0, were p-type. The resistivity of the layers remained unchanged for low dopant supply rates, but increased abruptly when the dopant supply rate was increased beyond a certain value. On the other hand, layers grown at 325°C with Te/Cd ratios from 0.1 to 0.25 were n-type. A maximum free electron concentration of 1.3 9 10 17 cm À3 was obtained at room temperature. The types and conductivities of the grown layers were strongly dependent on the growth conditions.

“…Details of the direct growth of single-crystal CdTe epitaxial films on the Si substrates in the MOVPE reactor are reported elsewhere. 7,8 The crystallinity and orientation of the grown films were evaluated by the X-ray diffraction (XRD) measurement using Cu K a as the X-ray source. The 4.2 K photoluminescence (PL) measurement using excitation from an Ar + -ion laser (514.5 nm) was used to evaluate the crystalline quality of the films.…”

Section: Methodsmentioning

confidence: 99%

Fabrication and Characterization of MOVPE-Grown CdTe-on-Si Heterojunction Diode-Type Gamma-Ray Detectors

Yokota

Yasuda

Niraula

et al. 2008

Self Cite

We report on the growth of very thick (>260 lm) high-crystalline-quality single-crystal CdTe epitaxial films on (211) Si substrates in a metalorganic vapor-phase epitaxy reactor, and the development of gamma ray detectors and their radiation detection properties. Films were grown with a high growth rate varying from 40 lm/h to 70 lm/h. A heterojunction diode was fabricated by growing a 90-lm-thick CdTe layer on an n + -Si substrate, which exhibited good rectifying behavior and had a low reverse bias leakage current of 0.18 lA/cm 2 at 100 V bias. The diode clearly demonstrated its gamma radiation detection capability by resolving energy peaks from the 241 Am radioisotope during roomtemperature measurements. By cooling the diode detector to -30°C, the leakage current could be reduced by three orders of magnitude from the roomtemperature value. At this operating condition dramatic improvements in the pulse height spectrum were observed.