Anomalous defect structure formed on GaSb surface by low temperature Sn ion-implantation and its formation mechanism

Noriko Nitta, Masafumi Taniwaki, Tomoo Suzuki, Yoshihiko Hayashi, Yuhki Satoh, Toshimasa Yoshiie

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12 Citations (Scopus)

Abstract

Defect formation in (100) GaSb by 60 keV Sn+ ion-implantation At 150-153 K is investigated using cross-sectional TEM, SEM and EDX. An anomalous structure consisting of many cells, which looks like a honey comb, was formed on the surface implanted with 8×1018 ions/m2. The diameter and the depth of a cell were about 50 nm and 220-250 nm respectively, and the thickness of the walls partitioning the cells was about 10 nm. The upper part of the partitioning wall is amorphous and rich in Ga, while the lower part shows crystalline structure. A heavy strain region with 50 nm thickness, corresponding to the maximum depth of the projected Sn ions, was observed under the cells. This defect structure is compared with similar defects which have been observed by other researchers. The defect formation mechanism is discussed, and an explanation based on movement of the implantation induced point defects is proposed. It is assumed that hills and hollows are formed in the early stage of implantation. The point defects created on the hills do not contribute to the development of the defect structure, because they annihilate almost completely by the recombination of vacancy and interstitial and by the movement to the near surface sink. However, under the hollows, vacancies remain which escaped recombination, and the interstitial atoms, which are highly mobile at low temperatures, migrate far from there to aggregate under the hills. The hollows become deeper by the movement of the remaining vacancies to the surface, and the hills develop into the walls by the migration of the interstitial atoms from the surrounding hollows.

Original languageEnglish
Pages (from-to)1141-1147
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume64
Issue number12
DOIs
Publication statusPublished - 2000 Jan 1

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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