Effects of nitrogen doping and working pressure on the crystallization of GeiSb4Te7 thin films for PRAM applications

Hyung Keun Kim, Seung Yun Lee, Doo Jin Choi, Sangwoo Shin, Hyung Hee Cho, Jae Sung Roh

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Abstract

The phase change random access memory (PRAM) has recently been ascending to become the most potential candidate for the next-generation nonvolatile memory. In this paper, we deposited Ge1Sb4Te7 as a phase change material on a glass substrate by DC magnetron sputtering at various working pressures of 5 × 10-3, 9 × 10-3 and 13 × 10-3 Torr and we performed nitrogen doping by flowing nitrogen gas during deposition. To verify the nitrogen doping we analyzed the secondary ion mass spectrometry (SIMS) data and observed the presence of nitrogen-doping contents. We measured the sheet resistance and the thickness reduction. We observed a reduction of the sheet resistance and the thickness of the films that had been annealed, we also observed an increase of the sheet resistance from 4.3 × 103 Ohm/sq to 2.8 × 105 Ohm/sq with additional nitrogen doping after annealing in the case of the film deposited at 9 × 10-3 Torr. Through the 3-w thermal conductivity measurements, we observed an increase in the thermal conductivity from 0.37 to 0.49 W/mK and a decrease with nitrogen doping from 0.49 to 0.43 for the films that had been annealed. In X-ray diffraction (XRD) results, FCC and HCP peaks were observed at annealing temperatures of 175 °C and 300 °C and the role of nitrogen doping that disturb the crystallization during a phase change was also observed.

Original languageEnglish
Pages (from-to)1896-1900
Number of pages5
JournalJournal of the Korean Physical Society
Volume55
Issue number5 PART 1
DOIs
Publication statusPublished - 2009 Nov 1

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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