Impacts of doping on epitaxial germanium thin film quality and Si-Ge interdiffusion

Guangnan Zhou, Kwang Hong Lee, Dalaver H. Anjum, Qiang Zhang, Xixiang Zhang, Chuan Seng Tan, Guangrui Xia

Research output: Contribution to journalArticlepeer-review


Ge-on-Si structures with three different dopants (P, As and B) and those without intentional doping were grown, annealed and characterized by several different material characterization methods. All samples have a smooth surface (roughness < 1.5 nm), and the Ge films are almost entirely relaxed. B doped Ge films have threading dislocations above 1 × 108 cm-2, while P and As doping can reduce the threading dislocation density to be less than 106 cm-2 without annealing. The interdiffusion of Si and Ge of different films have been investigated experimentally and theoretically. A quantitative model of Si-Ge interdiffusion under extrinsic conditions across the full xGe range was established including the dislocationmediated diffusion. The Kirkendall effect has been observed. The results are of technical significance for the structure, doping, and process design of Ge-on-Si based devices, especially for photonic applications.

Original languageEnglish (US)
Pages (from-to)1117-1131
Number of pages15
JournalOptical Materials Express
Issue number5
StatePublished - May 1 2018

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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