Development of nonspiking ohmic contacts to n-Ga(or Al)0.5 In0.5P and low temperature processed ohmic contacts to n-GaAs via solid phase reactions /
In this study, Si/Pd based ohmic contact structures are
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=736823981&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | In this study, Si/Pd based ohmic contact structures are developed to form nonspiking ohmic contacts to n-Ga(or AI)[]In[]P based on the solid phase regrowth principle to enhance the tunneling current across the metal-semiconductor junction barrier, thus resulting in tunneling ohmic contacts. For the Si/Pd contact on nAl[]In[]P, specific contact resistivity of about 6 x 10-6 [] cm2 can be obtained. This contact structure shows good surface and interface morphologies with contact protrusion into the n-Al[]In[]P substrate < 100 []. The solid phase regrowth process responsible for the ohmic contact formation was verified using cross-sectional transmission electron microscopy. For the Si/Pd ohmic contacts to Ga[]In[]P and GaAs/Ga[]In[]P structures, the minimum contact resistivities obtained were 2 x 10-5 [] cm2 and 4 x 10-6 [] cm2, respectively. Ohmic contact formation mechanism based on solid phase regrowth process is also proposed to rationalize the low contact resistance of the Si/Pd ohmic contact to Ga[]In[]P. For Si/Pd ohmic contacts to GaAs/Ga[]In[]P structures, the contact resistivity is found to be dependent on the thickness of the GaAs layer. A qualitative model is proposed to explain this dependence. In addition, a Au/Ge/Pd based ohmic contact structure is developed which can form low resistance ohmic contacts to n-GaAs at annealing temperature as low as 175 []C. This contact structure has various desired properties such as low contact resistivity, good surface morphology, shallow contact protrusion, Au wire bondability. The ohmic contact formation mechanism is investigated by means of transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS), and secondary ion mass spectrometry (SIMS), and is found to be related to the solid phase regrowth process, and interdiffusion between Au and Ge. An ohmic contact formation model is proposed based on the TEM, RBS and SIMS results. The electrical properties of this Au/Ge/Pd/n-GaAs structure annealed in the temperature range of 150 - 450 []C is also studied, and is related to the metallurgical reactions of the contact structure. |
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| Item Description: | Vita. "Major Subject: Electrical Engineering". In title, symbols are used. |
| Physical Description: | xviii, 113 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 107-112. |