Controllable Doping of CdTe and Formation of PN Junction Diodes by Backside Laser Irradiation

Nishizawa, Jun–ichi; Nakagawa, Hisaya; Zelenska, Kateryna; Gnatyuk, V. A.; Koike, Akifumi; Aoki, Toru

doi:10.1109/nss/mic42101.2019.9059751

Cited by 1 publication

(3 citation statements)

References 17 publications

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“…Metal-CdTe Schottky diodes have been generally fabricated and used as X-and γ-ray detectors. (2)(3)(4)(5)9,12,20,21) On the other hand, In/CdTe/Au barrier structures formed by frontside (5)(6)(7) or backside laser irradiation (16)(17)(18)(19) have been considered as p-n junction diodes, which have also shown high detection efficiency. Figure 2 shows the schematic of the structures of In/CdTe/Au X-and γ-ray detectors formed as (a) a Schottky diode (without laser irradiation) and (b) a p-n-junction diode by backside laser irradiation.…”

Section: Resultsmentioning

confidence: 99%

“…A p-n junction was created in the CdTe subsurface layer by laser-induced backside doping with In atoms from the deposited In electrode, which served as the dopant source. (16)(17)(18)(19) A schematic of the experimental setup for the laser-induced doping procedure is shown in Fig. 1.…”

Section: Methodsmentioning

confidence: 99%

“…The optimal conditions for laser-induced backside doping were studied and estimated in our earlier publications. (16)(17)(18)(19) The selected laser energy in the experiments was E = 11 mJ for which the temperature of the In surface at the In/CdTe interface increased up to near the In melting point. The number of laser pulses, used for backside doping, was 30.…”

Section: Methodsmentioning

confidence: 99%

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Effects of Heating on Electrical and Spectral Properties of In/CdTe/Au X- and γ-ray Detectors with a Schottky Barrier or Laser-induced p–n Junction

Nishizawa¹,

Gnatyuk²,

Zelenska³

et al. 2020

Sensors and Materials

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The CdTe semiconductor has been used for X-and γ-ray imaging detectors owing to its sensitivity to ionizing radiation, high energy and spatial resolution, and ability to operate at room temperature. However, it is challenging to grow large-diameter CdTe. Therefore, we aim to develop large-area high-resolution X-ray imaging sensors by tiling small CdTe wafers. Postprocessing, bonding, and tiling require the heating of detectors; therefore, it is important to develop high-thermal-tolerance radiation sensors. We have fabricated two types of In/CdTe/Au diode detector (with a Schottky barrier and a p-n junction) using identical crystals and the same technological procedures except laser irradiation, and examined their resistance to heat treatment. The diodes with an In/CdTe rectifying contact and a p-n junction, formed by the laser-induced backside doping of the CdTe subsurface layer with In, had similar electrical and spectral characteristics, which did not significantly change after heating at temperatures below the In melting point (156 ℃). The Schottky diodes, subjected to heating at 200 and 300 ℃, exhibited the deterioration of the electrical characteristics (reverse dark current increased) and lost their detection ability. In contrast, the p-n junction diodes demonstrated highly stable I-V characteristics, and the measured 241 Am radioisotope emission spectra did not degrade even after melting and solidifying the In electrode.

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