Comment On 'use Of Si~+ Pre-ion-implantation On Si Substrate To Enhance The Strain Relaxation Of The Ge_xsi_(1-x) Metamorphic Buffer Layer For The Growth Of Ge Layer On Si Substrate' [appl. Phys. Lett. 90, 083507 (2007)]

摘要

In a recent letter, Hsieh et al. reported the growth of high-quality Ge epilayers with a SiGe buffer thickness of only 0.45 μm, a surface root-mean-square roughness of less than 0.4 nm, and a threading dislocation of 7.6 × 10~6 cm~(-2) on Si~+ pre-ion-implantation Si substrate utilizing of strain relaxation enhancement by point defects and interface blocking of the dislocations. Our comment has focused on x-ray diffraction data shown in Fig. 3 of Ref. 1. We demonstrate that the strain in Ge epilayers is tensile, rather than compressive as misunderstood by the authors.