Si/SiGe heterostructures: from material and physics to devices and circuits

Abstract

Silicon germanium (SiGe) has moved from being a research material to accounting for a small but significant percentage of manufactured semiconductor devices. This percentage is predicted to increase substantially as SiGe begins to be used in complementary metal oxide semiconductor (CMOS) technology in the future to substantially improve performance. It is the development of Si/SiGe heterostructures which has enabled band structure and strain engineering allowing Si/SiGe to be used in many different ways to improve conventional microelectronic device performance along with allowing new concepts to be explored. This paper presents a review of the material properties, growth techniques, band structure and the main electronic devices of the Si/SiGe heterostructure system. In particular, the important device technologies in mainstream microelectronics of the SiGe heterostructure bipolar transistor (HBT) and strained-Si CMOS will be reviewed before future device and optoelectronics concepts are explored.

Imaging Structure and Composition Homogeneity of 300 mm SiGe Virtual Substrates for Advanced CMOS Applications by Scanning X-ray Diffraction Microscopy

“…Second, the bulk properties of the Si 0. 3 Ge 0.7 layer as probed by the K-Map technique are not necessarily manifested in the surface morphology measured by AFM. We thus conclude that, upon comparing the lattice tilt images of polished and unpolished samples, we succeeded to directly quantify the lattice tilt induced by dislocation strain fields with, if any, only minor contributions from the surface undulation.…”

“…The constant composition Si 0. 3 Ge 0.7 layer of the as-grown unpolished sample is 1.6 μm thick, which is the focus of our investigations. A nominally identical sample was processed by CMP removing the topmost 600 nm.…”

“…The new Scanning X-ray Diffraction Microscopy (SXDM) technique K-Map, recently developed at beamline ID01 at the European Synchrotron Radiation Facility (ESRF), was applied to directly image the structural parameters of the Si 0. 3 Ge 0.7 layer on a micrometer scale (Figure 1d). 16 Here, X-rays with 8 keV were focused by a Fresnel zone plate (FZP) with a beam stop (BS) and an order sorting aperture (OSA) to the center of rotation of the goniometer.…”

“…1,2 Furthermore, highly complex electronic−photonic integrated circuits (EPICs), e.g., wireless SiGe mixed signal radiofrequency technology with photonic sensing applications, are achieved using new materials integrated on Si following "More than Moore" approaches. 3 To address the vision of a monolithically integrated light source module in a Si CMOS environment, intense research on the integration of III−V materials as well as that on band gap engineering of group IV semiconductors is applied to achieve direct band gap materials either in the form of strained Ge or SiGeSn alloy systems. 4,5 For these purposes, Germanium virtual substrates (VS) on large diameter Si wafers are considered as a central materials platform to enable these advanced technologies.…”

“…A 2D real space area is mapped to render a complete quantitative description of the local lattice tilt, strain, and composition fluctuation of Si 0. 3 Ge 0.7 films on a step graded buffer.…”