Nanoelectronic device applications of a chemically stable GaAs structure

Abstract

Janes, David B.; Kolagunta, V. R.; Batistuta, M.; Walsh, B. L.; Andres, Ronald P.; Liu, Jia; Dicke, J.; Lauterbach, J.; Pletcher, T.; Chen, E. H.; Melloch, Michael R.; Peckham, E. L.; Ueng, H. J.; Woodall, Jerry M.; Lee, Takhee; Reifenberger, R.; Kubiak, C. P.; and Kasibhatla, B., "Nanoelectronic device applications of a chemically stable GaAs structure" (1999 We report on nanoelectronic device applications of a nonalloyed contact structure which utilizes a surface layer of low-temperature grown GaAs as a chemically stable surface. In contrast to typical ex situ ohmic contacts formed on n-type semiconductors such as GaAs, this approach can provide uniform contact interfaces which are essentially planar injectors, making them suitable as contacts to shallow devices with overall dimensions below 50 nm. Characterization of the native layers and surfaces coated with self-assembled monolayers of organic molecules provides a picture of the chemical and electronic stability of the layer structures. We have recently developed controlled nanostructures which incorporate metallic nanoclusters, a conjugated organic interface layer, and the chemically stable semiconductor surface layers. These studies indicate that stable nanocontacts (4 nmϫ4 nm) can be realized with specific contact resistances less than 1ϫ10 Ϫ6 ⍀ cm 2 and maximum current densities (1ϫ10 6 A/cm 2 ) comparable to those observed in high quality large area contacts. The ability to form stable, low resistance interfaces between metallic nanoclusters and semiconductor device layers using ex situ processing allows chemical self-assembly techniques to be utilized to form interesting nanoscale semiconductor devices. This article will describe the surface and nanocontact characterization results, and will discuss device applications and novel techniques for patterning close-packed arrays of nanocontacts and for imaging the resulting structures.

Self-assembled metal/molecule/semiconductor nanostructures for electronic device and contact applications

“…27 The difference in the contact properties between the samples can be qualitatively explained by the better surface stability of p-doped LTG:GaAs and the presence of mid-gap states near the Fermi level in this material. 26,27 The I(V) shape difference between measurements over the cluster and over the XYL-coated surface can also be qualitatively explained by the work function difference between the Au nanocluster and the Pt/Ir tip and the resulting surface barrier height difference between the two cases.…”

Retarding Field Analyzer for Ion Energy Distribution Measurement Through a Radio‐Frequency or Pulsed Biased Sheath

“…Retarding field energy analyzers (RFEA's) have been used to measure IEDs at grounded [1][2][3][4][5][6][7][8][9][10][11][12][13] and driven electrodes [14][15][16][17][18][19][20] in rf discharges in recent decades. The RFEA has been employed mostly at grounded surfaces as this simplifies the RFEA data acquisition electronics.…”

“…Measurements made at rf driven electrodes are more difficult but have been achieved using techniques that allow the RFEA (and measurement electronics) to float at rf bias potential. The list of references [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] is by no means all inclusive but along with the references therein should serve as a useful overview of the important contributions and advances made by precedent researchers. Here, a floating RFEA design is presented for use at either a grounded or rf driven electrode in a plasma discharge.…”

Surface Chemistry of Mercaptan and Growth of Pyridine Short-Chain Alkoxy Silane Molecular Layers

“…The ability to modify the chemistry of a surface yet retain the bulk properties of the substrate has profound importance for many and diverse applications. Some of these applications include tribology, interfacial bonding, corrosion inhibition, diffusion barriers for metallic diffusion into dielectrics, passivation layers for II−VI and III−V compound semiconductors, improvement of substrate biocompatibility, and promotion of the wetting of metals deposited on dielectrics. In particular, 3-mercaptopropyltrimethoxysilane has been used for passivation of Ga−As, for copper chemical vapor deposition, , as a heavy metal ion adsorbent, − and for protein immobilization. , However, despite the potential widespread application of molecular layer chemistry little work has been undertaken to characterize the growth of short-chain alkoxy silanes and in particular mercaptan- and pyridine-terminated silanes.…”