Low-Temperature Growth of Epitaxial Semiconductor Nanostructures and Films
- PDF / 757,465 Bytes
- 3 Pages / 612 x 792 pts (letter) Page_size
- 58 Downloads / 215 Views
Low-Temperature Growth of Epitaxial Semiconductor Nanostructures and Films Alp T. Findikoglu1, Daniel E. Perea2, and S. T. Picraux2 1
MPA-STC, Los Alamos National Laboratory, MS T004, Los Alamos, NM 87545, U.S.A.
2
MPA-CINT, Los Alamos National Laboratory, MS K771, Los Alamos, NM 87545, U.S.A.
ABSTRACT The growth of epitaxial semiconductor nanostructures and films at low temperatures is important for semiconductor technology because it allows the possibility of monolithically integrating different high-performance single-crystalline semiconductor structures directly onto low cost technologically important substrates. At sufficiently low temperatures this can enable, for example, Si or Ge device fabrication on flexible substrates such as plastics. We have studied the reduced-temperature liquid-mediated growth of Ge nanostructures and films on crystalline template layers on non-single-crystalline substrates in a low-pressure chemical vapor deposition (LPCVD) system. The heteroepitaxial process is implemented by the Au seeded vapor-liquidsolid (VLS) catalytic growth technique with germane below 400 ºC. Crystalline template layers were prepared with ion-beam-assisted-deposition (IBAD) texturing and electron-beam evaporation on glass substrates. A thin layer of e-beam evaporated Au forms the catalyst layer, upon which we grew Ge films at 386 ºC. Scanning electron microscopy and x-ray diffraction results indicated that both Ge islands and nanowires grew heteroepitaxially on the crystalline template layers on glass substrates with good alignment over large areas. INTRODUCTION The main research objective of this work is to control and optimize the vapor-liquid-solid (VLS) catalytic growth process of a semiconductor film on an ion-beam-assisted-deposited (IBAD) crystalline buffer layer to enable epitaxial growth at reduced temperatures. The ultimate goal of this research is to demonstrate epitaxial growth of Si and Ge nanostructures and films on crystalline buffer layers on plastics. Epitaxy is crucial to most semiconductor devices because it is usually the only method for achieving high crystalline quality growth, with corresponding good electronic and optical properties. A practical method to allow epitaxial semiconductor nanostructure and film growth on plastics would be an important advancement for the semiconductor industry because it would enable high-performing electronics, optics, sensors, displays, and photovoltaics on inexpensive, large-area, low-weight, flexible, and multi-functional substrates. The control of surface wetting and layer growth on IBAD buffers differentiates this method from existing VLS growth methods for nanowires on wafers [1]. Also, we deliver high purity Si and Ge from the gas phase. This is in contrast to conventional Liquid-Phase growth methods, which use a Si-metal melt within a boat. Films grown from such a melt exhibit high levels of impurities and crystalline defects, as well as morphological features not suitable for most thin-film electronics and optics applications [2]. In this wor
Data Loading...
