Strained-Layer Semiconductor Research and Development at Sandia

Abstract

Sandia National Laboratories pioneered work in strained‐layer superlattice systems for electronics and optoelectronics. Based on that work, it now conducts research and development in compound semiconductor and optoelectronics physics, materials science, and device technology. Although Sandia's research relies heavily on theoretical and experimental solid state physics, this paper will emphasize applications that exploit the properties of strained‐layer systems. This research allows the microelectronics and photonics community to use the special properties of strained‐layer systems in an engineering, rather than an empirical, manner. The number of electronic and optoelectronic devices that depend on strained‐layer systems for their highest performance with device applications indicates their importance. Selected strained‐layer structures and devices developed at Sandia will be discussed.

Stresses and strains in epilayers, stripes and quantum structures of III - V compound semiconductors

“…Strain plays an important role in pseudomorphic strainedlayer devices. Devices based on GeSi/Si [57,61,66] and III-V compound semiconductors [91,97] have been designed and fabricated with enhanced performance. Strain provides another degree of freedom to tailor the band structure and modify optical and transport properties of semiconductors.…”

Optical Determination of the Heavy-hole Effective Mass of (In, Ga)As/ GaAs Quantum Wells

“…In recent years, opto-electronic properties of strained (In, Ga)As/GaAs quantum wells have been widely investigated because these structures play pivotal roles in providing basic understanding on low-dimensional systems and new concepts in various device applications such as quantum-well lasers, detactors, optical modulators, and strained quantum well field effect transistors(SQWFET) [1]. The importance of stained (In, Ga)As/GaAs quantum wells is that they provide structures with band gaps in the infrared spectral regions around 0.98 m. The laser chip operating at this wavelength is useful as a pump source for Er-doped fiber amplifier.…”

Effects of Pressure on GaAs/InxGa1-xAs/AlAs Resonant Tunneling Structures

“…The following equation can be obtained; . (12) where V d and i d are the bias voltage and current flow in the RTS, respectively. The next simplification will be to approximate the I-V curve between D to A and B to C through linear functions, so that g is constant in the two positive resistance regions.…”

“…(9,10) Pressure or stress plays a very important role in the investigation of the transport properties of semiconductor materials and offers a possibility of designing heterostructure devices with customized performances. (11,12) All III-V compounds are piezoelectric owing to the polar character of the bonds between their different atoms. The piezoelectric effect can cause internal electric fields in III-V semiconductor heterostructures if the polarization fields have a nonvanishing component in the direction perpendicular to the interfaces and differ in magnitude and/or sign between the different layers.…”