Chemischer InformationsdienstVolume 11, Issue 34 Physical Inorganic Chemistry ChemInform Abstract: RECTIFYING AND OHMIC CONTACTS TO GALLIUM INDIUM ARSENIDE PHOSPHIDE D. V. MORGAN, D. V. MORGANSearch for more papers by this authorJ. FREY, J. FREYSearch for more papers by this authorW. J. DEVLIN, W. J. DEVLINSearch for more papers by this author D. V. MORGAN, D. V. MORGANSearch for more papers by this authorJ. FREY, J. FREYSearch for more papers by this authorW. J. DEVLIN, W. J. DEVLINSearch for more papers by this author First published: August 26, 1980 https://doi.org/10.1002/chin.198034014Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume11, Issue34August 26, 1980 RelatedInformation

Molecular beam epitaxy has been used in a continuous growth procedure to form GeGaAs epitaxial structures that were suitable for MESFET fabrication. Near surface doping profiles were engineered such that low resistance ohmic contacts to the GaAs layer were obtained by subsequently depositing a metal overlayer on the Ge surface. Evaporated Au overlayers yielded specific contact resistances of the order of 10−6ω cm2 without heat treatment. Because the conventional alloying procedure now appeared superfluous, metallurgically non-reactive systems were investigated with a view to constructing GaAs MESFETs with entirely refractory metallizations. Sputtered molybdenum has been evaluated for both the formation of ohmic contacts to the Ge/GaAs layers and rectifying contacts to the GaAs layer. Damage introduced as a result of the sputtering deposition process is the probable cause of non-ideality in the as-prepared Schottky barriers. However, forward bias current-voltage ideality factors of n = 1.07 have been obtained after annealing.

Capacitance/voltage and current/voltage measurements of r.f. sputtered Au-Mo contacts to epitaxial n/n+ GaAs indicate that compensating damage centres are introduced into the near-surface region of GaAs during the sputtering process. The concentration of these damage centres may be reduced by annealing. For comparison, the net doping profiles in the GaAs were established via independent thermally ...

Two types of device have been fabricated, a heated surface and an unheated surface. For heated surface devices the barrier heights measured by a variety of techniques are consistent with each other and with the results reported by other workers. Unheated devices, however, exhibit inconsistencies which are attributed to an interfacial oxide film.

Material fabricated with the geometry of transferred electron devices can be characterized using the geometric magnetoresistance technique, GMR. It is shown how the technique can be used to study the mobility of GaAs transferred electron and to relate these mobility measurements to modulation noise in Gunn oscillators. The effect on non-ohmic contacts on the interpetation of GMR results is also analysed with particular reference to contacts on InP material. A simple equivalent circuit is presented to enable the true mobility to be extracted from the experimental results in the case of Ag, Ag/Sn, and Sn contacts. Materialien, die mit der Geometrie von Elektronentransferbauelementen hergestellt werden lassen sich durch die geometrische Magnetowiderstandstechnik, GMR, charakterisieren. Es wird gezeigt, wie die Technik zur Untersuchung der Beweglichkeit von GaAs-Transferelektronen benutzt werden kann und diese Beweglichkeitsmessungen mit dem Modulationsrauschen in Gunnoszillatoren verknüpft werden kann. Der Einfluß nicht-ohmscher Kontakte für die Interpretation der GMR-Ergebnisse wird in spezieller Hinsicht auf die Kontakte auf InP-Material analysiert. Es wird ein einfaches Äquivalentschaltbild angegeben, um die wahre Beweglichkeit aus den experimentellen Ergebnissen in den Fällen von Ag-, Ag/Sn- und Sn-Kontakten zu erhalten.

The GMR technique has been used to evaluate contact properties in completed InP transferred electron devices. Devices made on the same layer but with different contacts, Sn dot, Ag/Sn and Ag, have respectively displayed more enhanced Schottky barrier behaviour in their I-V characteristics and in GMR measurements as a function of bias, ¿(V). At room temperature a model involving a low height barrier, series resistance and a resistance in parallel with the barrier has been fitted to the measured I-V of an Ag/Sn contact device and the results used to correct the asymmetrical ¿(V) to give the bulk mobility variation.