THM Growth and Characterization of 100 mm Diameter CdTe Single Crystals

Abstract

The THM growth technology for 100 mm diameter CdTe single crystals has been intensively developed. In consequence of the optimization of growth conditions, we have succeeded in controlling growth interface shape and growing 100 mm diameter CdTe single crystals with 300 mm in length. Concerning the behavior of Te inclusions in the grown crystal, their size and density were investigated by IR transmission microscopy. The size distribution of Te inclusions was divided into two groups, and the density of them was less than 1 10 5 cm 3 . Charge transport properties of the grown crystal were investigated by using the " -model" spectral fitting method, and were found to be quite uniform all over the wafer. To investigate the homogeneity of radiation detector performances, Ohmic type and Schottky type detectors with 4 mm 4 mm 1 mm were fabricated from the left half and the right half of the 100 mm diameter wafer, respectively. Standard deviations of their energy resolutions for the 122 keV line from 57 Co were less than 6%. This excellent uniformity is essential for the room temperature semiconductor detectors in the major application areas, such as medical imaging, non-destructive inspection and homeland security.

CdTe/CZT under high flux irradiation

“…The progress in crystal growth during the recent 40 years allowed a steady increase of the diameter of available single crystals. Ingots of a diameter of up to 4 inch are currently available [5][6][7]. In parallel the crystal quality was continuously improved and high single crystal yield was obtained.…”

Growth and interface study of 2in diameter CdZnTe by THM technique

“…In the recent years travelling heater method (THM) technique has proven to be the most viable technique to grow large diameter CdTe (100 mm diameter) and CZT(75 mm diameter), with good composition uniformity and better yield [13][14][15]. Due to the lower temperature growth process, much below than the melting point, THM has many advantages over melt growth technique.…”

Microstructural, optical and electrical properties of Cl-doped CdTe single crystals

“…The fabricated CdTe radiation detectors can be operated at room-temperature due to the favorable band gap (1.44 eV) and have been researched by various groups [1][2][3][4][5][6][7].…”

“…In this connection, Cl doping for annihilating all these point defects (i.e. Cd-vacancies and Te inclusions) can be an effective way to obtain semi-insulating (above 10 9 Ω·cm) high-quality CdTe material [2,8,9,13,14].…”