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Making Esaki Diodes

IP.com Disclosure Number: IPCOM000098513D
Original Publication Date: 1960-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Dill, EH: AUTHOR

Abstract

It has been discovered that germanium is a sufficiently strong donor in gallium arsenide to make Esaki diodes. When germanium in a suitable carrier metal such as gold is alloyed into degenerate p-type gallium arsenide, Esaki junctions result. These junctions show good peak to valley current ratios and high current densities characteristic of good Esaki junctions obtained in gallium arsenide by other means.

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Making Esaki Diodes

It has been discovered that germanium is a sufficiently strong donor in gallium arsenide to make Esaki diodes. When germanium in a suitable carrier metal such as gold is alloyed into degenerate p-type gallium arsenide, Esaki junctions result. These junctions show good peak to valley current ratios and high current densities characteristic of good Esaki junctions obtained in gallium arsenide by other means.

In general, germanium can be either a donor or an acceptor because of the fact that it has four valence electrons. The effect which it has upon the lattice depends upon the position it takes in the lattice. In this instance germanium is believed to enter the gallium arsenide lattice substitutionally for the gallium, thus yielding donors preferentially.

The carrier metal for the germanium used is gold in the form of 17% Ge- 83% Au shot. The germanium is spectroscopically pure and the solubility of gold is sufficiently low in GaAs so as not to contribute a significant concentration of impurities itself. The device is formed by the alloy process at around 500 degrees C with the regrown region becoming n-type GaAs with a donor concentration in excess of 10/19/ Ge/cm3. A base tab of kovar is used with an ohmic contact between the kovar and the GaAs formed by a Zn-Au solder. I(p)/I(v) ratios of 15-20 to 1 and current densities I(p)/A in the vicinity of 1000 A/cm2 are obtained. Other metals such as silver would serve as equally well as gold for the...