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Neutralization of Misfit Dislocations in Silicon-Germanium Devices Using Hydrogenation

IP.com Disclosure Number: IPCOM000034599D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Iyer, SS: AUTHOR [+3]

Abstract

A technique is described whereby the recombination effects of misfit dislocations (MFDs) are reduced in Si-Ge structures by using hydrogenation. The result is a reduction in leakage currents and an improved radiative recombination. In the fabrication of band gap engineered devices, such a hetero- junction bipolar transistors and modulation doped field-effect transistors, for direct gap and resonant tunnelling applications, the use of Si-Ge structures generally requires that the layers of the structure be strained. The strain causes MFDs to generate at the interfaces. They are usually initiated by process aberrations, such as impurities at the surface, temperature instabilities during growth, doping effects, edge effects, etc. The net result is two-fold: a reduction of strain and an increase in recombination.

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Neutralization of Misfit Dislocations in Silicon-Germanium Devices Using Hydrogenation

A technique is described whereby the recombination effects of misfit dislocations (MFDs) are reduced in Si-Ge structures by using hydrogenation. The result is a reduction in leakage currents and an improved radiative recombination. In the fabrication of band gap engineered devices, such a hetero- junction bipolar transistors and modulation doped field-effect transistors, for direct gap and resonant tunnelling applications, the use of Si-Ge structures generally requires that the layers of the structure be strained. The strain causes MFDs to generate at the interfaces. They are usually initiated by process aberrations, such as impurities at the surface, temperature instabilities during growth, doping effects, edge effects, etc. The net result is two-fold: a reduction of strain and an increase in recombination. While a strain reduction may be compensated, to some extent, by the design of the structure, MFDs are a serious detractor from device performance. The concept described herein reduces the deleterious effect of MFDs through the use of hydrogenation. A strained layer superlattice was grown under conditions that would generate many MFDs. This was a six-period Si(0.88)-Ge(0.12)/Si superlattice with 200 nm period. The MFDs were observed by means of a transmission electron microscope such that a photoluminescence (PL) spectra taken at 9.8K was produced, as shown in the figure. Th...