Reduction of threading dislocation density in Ge/Si using a heavily As-doped Ge seed layer

作者：Lee Kwang Hong; Bao Shuyu; Wang Bing; Wang Cong; Yoon Soon Fatt; Michel Jurgen; Fitzgerald Eugene A; Tan Chuan Seng

来源：AIP Advances, 2016, 6(2): 025028.

DOI：10.1063/1.4943218

High quality germanium (Ge) epitaxial film is grown directly on silicon (001) substrate with 6. off-cut using a heavily arsenic (As) doped Ge seed layer. The growth steps consists of (i) growth of a heavily As-doped Ge seed layer at low temperature (LT, at 400 degrees C), (ii) Ge growth with As gradually reduced to zero at high temperature (HT, at 650 degrees C), (iii) pure Ge growth at HT. This is followed by thermal cyclic annealing in hydrogen at temperature ranging from 600 to 850 degrees C. Analytical characterization have shown that the Ge epitaxial film with a thickness of similar to 1.5 mu m experiences thermally induced tensile strain of 0.20% with a treading dislocation density (TDD) of mid 10(6)/cm(2) which is one order of magnitude lower than the control group without As doping and surface roughness of 0.37 nm. The reduction in TDD is due to the enhancement in velocity of dislocations in an As-doped Ge film.

• 出版日期2016-2