Article

Nanoscale holographic interferometry for strain measurements in electronic devices.

CEMES-CNRS, nMat Group, 29 rue Jeanne Marvig, 31055 Toulouse, France.
Nature (Impact Factor: 42.35). 07/2008; 453(7198):1086-9. DOI: 10.1038/nature07049
Source: PubMed

ABSTRACT Strained silicon is now an integral feature of the latest generation of transistors and electronic devices because of the associated enhancement in carrier mobility. Strain is also expected to have an important role in future devices based on nanowires and in optoelectronic components. Different strategies have been used to engineer strain in devices, leading to complex strain distributions in two and three dimensions. Developing methods of strain measurement at the nanoscale has therefore been an important objective in recent years but has proved elusive in practice: none of the existing techniques combines the necessary spatial resolution, precision and field of view. For example, Raman spectroscopy or X-ray diffraction techniques can map strain at the micrometre scale, whereas transmission electron microscopy allows strain measurement at the nanometre scale but only over small sample areas. Here we present a technique capable of bridging this gap and measuring strain to high precision, with nanometre spatial resolution and for micrometre fields of view. Our method combines the advantages of moiré techniques with the flexibility of off-axis electron holography and is also applicable to relatively thick samples, thus reducing the influence of thin-film relaxation effects.

0 Bookmarks
 · 
232 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This brief review describes the different types of semiconduc-tor quantum dot systems, their main applications and which types of microscopy methods are used to characterize them. Emphasis is put on the need for a comprehensive investigation of their size distribution, microstructure, chemical composi-tion, strain state and electronic properties, all of which influ-ence the optical properties and can be measured by different types of imaging, diffraction and spectroscopy methods in an electron microscope. Quantum dot systems
    Journal of Microscopy 11/2014; 00:1-8. · 1.63 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Holography - originally developed for correcting spherical aberration in transmission electron microscopes - is now used in a wide range of disciplines that involve the propagation of waves, including light optics, electron microscopy, acoustics and seismology. In electron microscopy, the two primary modes of holography are Gabor's original in-line setup and an off-axis approach that was developed subsequently. These two techniques are highly complementary, offering superior phase sensitivity at high and low spatial resolution, respectively. All previous investigations have focused on improving each method individually. Here, we show how the two approaches can be combined in a synergetic fashion to provide phase information with excellent sensitivity across all spatial frequencies, low noise and an efficient use of electron dose. The principle is also expected to be widely to applications of holography in light optics, X-ray optics, acoustics, ultra-sound, terahertz imaging, etc.
    Scientific Reports 11/2014; 4:7020. · 5.08 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The evolution of elastic strain engineering in nanostructures and devices requires characterization tools that can be used to not only observe but also quantify the actual strain in a sample, whether this strain is intrinsic or applied. Strain contrast in crystalline samples has always been one of the primary contrast mechanisms used for imaging the microstructure of a material in a transmission electron microscope (TEM). In this regard, TEM is a particularly powerful tool due to its ability to spatially resolve strain information with high precision and spatial resolution. This article reviews the techniques currently available for directly measuring strain in the TEM. Examples are given for measuring strain in semiconductor devices using imaging, diffraction, and holographic techniques. For strain measurement during in situ mechanical testing, two general methods are presented: the conversion of displacement from an actuation device or the direct measurement of strain using image features during deformation.
    MRS Bulletin 02/2014; 39(02):138-146. · 5.07 Impact Factor

Full-text

Download
56 Downloads
Available from
May 16, 2014