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Fabrication of Ultra Low Barrier Height SBD Structures Using Rare Earth Transition Meta Alloys

IP.com Disclosure Number: IPCOM000051370D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Howard, JK: AUTHOR

Abstract

Metal alloys (transition metal (TM)-rare earth (RE) to achieve phi beta

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Fabrication of Ultra Low Barrier Height SBD Structures Using Rare Earth Transition Meta Alloys

Metal alloys (transition metal (TM)-rare earth (RE) to achieve phi beta </approx. 0.4 eV SBD (Schottky barrier diode) structures are discussed The barrier height of Ta is approx.0.5 eV (N- Si), and the barrier height of rare earth (RE) metals to (N-)Si is approx.0.2-0.3 eV (nearly ohmic).[*]. The barrier height of Ta is constrained to be approx. 0.48 eV, at the lowest, for sputtered Ta/Si interfaces. However, the reverse properties of the Ta/Si structure are usually good. The rare earth - Si (or rare earth silicide) barrier height is approx. 0.2-0.4 eV, but the reverse breakdown and leakage properties are poor compared to Ta/Si.

This article proposes the deposition of transition metal (TM) - rare earth (RE) alloys to further lower the barrier height without sacrificing the reverse properties. The rare earth composition should be </approx. 50% (typically approx.10%). Various methods of deposition can be e as noted below. See Original.

A typical alloy would be 90/10% Ni-Y alloy, among the various combinations of TM-RE alloys in the above table.

Fig. 1 shows a structure where diffusion barrier alloys are employed.

Co-Deposition (alloys with differing vapor pressures)

Ta - Y (</approx. 10%) or other stable rare earth metals Ta - Gd (</approx. 10%).

Electron beam deposition (two guns) can also be employed where desired.

As a result, a layered alloy structure can be obtained,...