Ohmic contact metallizations to phosphrous based compound semiconductors by solid phase regrowth /
In this study, a new approach to form non-spiking and low
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739667961&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | In this study, a new approach to form non-spiking and low contact resistivity contacts to p-InP, p-InGaAsP, and n-GaP will be investigated by utilizing solid phase regrowth principle to enhance the tunneling current across the barrier, thus resulting in ohmic contact behavior. P-type indium phosphide (InP) and its related compounds, such as InGaAsP and GaP have been widely used for the fabrication of modern high speed electronic and optoelectronic devices. Low resistance and reliable ohmic contacts are required for superior device performance. The most common approach to fabricate ohmic contacts to p-InP and its related compounds involves the use of Au-based metallizations, such as Au:Zn and Au:Be contacts. It is generally believed that Zn or Be dopes the surface region of the substrates during annealing, resulting in an enhancement of tunneling current which leads to an ohmic behavior. Although Au-based p-type contacts yield satisfactory contact resistivity, there are several inherent problems, i.e., poor reliability, non-uniform surface and spiking interface and deep protrusion of Au into the substrate. These spikes and deep protrusions can cause problems during device operations. Thus, significant effort has been expended for the development of low resistance, shallow and non-Au-based ohmic contacts to p-InP and its related compounds. The new approach involves solid-phase reactions which result in either a heavily doped surface layer or a heterojunction on the substrates. Conventional evaporation and lift-off processes can be readily used in this approach to define the contact areas. Thus, non-spiking ohmic contacts based on solid phase reactions appear to be the simplest and, perhaps, the most practical schemes for device applications. We have developed the low-resistance and thermally stable non-spiking ohmic contact schemes based on the solid phase regrowth principle: (i) the Ge/Pd/Zn/Pd, Pd/Sb/Zn/Pd, and Zn/Pd contacts, to p-InP (ii) the Si/Pd and Al/Si/Pd contacts to n-GaP, and (iii) the Si/Pd/Zn/Pd and Ge/Pd/Zn/Pd contacts to p-InGaAsP. Also in order to further reduce contact resistivity, other ohmic contact schemes such as Au/Pd/Zn/Pd and Pd/Zn/Pd contacts to p-InGaAsP were investigated. Abnormal lateral Zn diffusion for the annealed Pd/Zn/Pd contacts to p-InP was studied. |
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| Item Description: | Vita. "Major Subject: Electrical Engineers". |
| Physical Description: | xviii, 166 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 156-165. |