Ion beam mixing of silicon-germanium thin films

Abstract

An overview of processing silicon-germanium (Si-Ge) alloys for various applications is presented here. Several methods of formation are briefly summarized. In particular, results of preliminary experiments on ion-beam mixing of Si-Ge layered structures deposited by physical vapor deposition and subsequently ion implanted with varying doses of argon are presented. Different layered structures have been designed and mixed to obtain optimal process conditions. The ion beam mixing process yields films with a gradual band-gap variation from 1.12 eV to 0.85 eV, thus allowing quite a wider spectrum of wavelengths to be absorbed. Rutherford backscattering spectrometry (RBS) has been used to characterize the nature and extent of the mixing of as-deposited and irradiated films.

Heteroatomic Si/Ge Zintl Clusters: Single‐Crystal Structure Determination of Rb4[Si7.8Ge1.2](NH3)5 and [Rb([18]crown‐6)Rb3][Si7.5Ge1.5](NH3)4

“…High‐performance applications in silicon microelectronics include silicon–germanium alloys, which compete with direct band–gap compound semiconductors such as GaAs 1. 2 The introduction of Ge in Si solar cells enhances the efficiency due to a considerably lower band gap 1.…”

“…High‐performance applications in silicon microelectronics include silicon–germanium alloys, which compete with direct band–gap compound semiconductors such as GaAs 1. 2 The introduction of Ge in Si solar cells enhances the efficiency due to a considerably lower band gap 1. For fabrication of these Si–Ge structures molecular beam epitaxy, plasma‐enhanced, and metal–organic chemical vapor deposition have been used 2–9.…”

“…The crystal structure of 1 is isotypic to [Rb( [18] 4 , which contains homoatomic [Si 9 ] 4À clusters. [29] Double layers of [Rb 3 Si 7.5(1) Ge 1.5 (1) ] À are separated by [18]crown-6-sequestered Rb + ions ( Figure 2). The RbÀSi/Ge bond lengths range from 3.468(2) to 4.099 (2) .…”

“…Section of the crystal structure of 1. Double layers of [Rb 3 Si 7.5(1) Ge 1.5(1) ] À are separated by[18]crown-6-sequestered Rb + ions. Heteroatomic clusters are drawn as gray polyhedra, crown ethers and ammonia molecules are schematically shown for clarity.…”

Properties of Interfaced Materials and Films: Part I

“…Examples of well-studied solid-solid interfaces in the literature include Si-SiO 2 16,17 and Ge-Si. 18,19 Recent developments in the bandgap engineering of strained monolayer and bilayer 2D materials 20 make the study of interfaces and films even more interesting and challenging.…”