Ohmic contacts to p- and n-type GaSb

Heinz, C.

doi:10.1080/00207218308938720

Cited by 31 publications

(8 citation statements)

References 9 publications

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“…For n-type contacts, an evaporation of 1008, tin followed by 20008, of gold was employed [8]. In this case, the unalloyed contact was definitely non-ohmic, and an anneal was required.…”

Section: Epitaxial Structures and Junction Processingmentioning

confidence: 99%

“…Since nonalloyed ohmic contacts appeared to produce adequately low specific contact resistances, the fabrication procedure was changed to avoid alloying the front contact. For some devices, the metallization was changed to 300A of titanium capped with 1 to 2 microns of silver.For n-type contacts, an evaporation of 1008, tin followed by 20008, of gold was employed [8]. In this case, the unalloyed contact was definitely non-ohmic, and an anneal was required.…”

mentioning

confidence: 99%

See 1 more Smart Citation

GaInSb and GaInAsSb thermophotovoltaic device fabrication and characterization

Hitchcock¹,

Gutmann²,

Borrego³

et al. 1997

Third NREL Conference on Thermophotovoltaic Generation of Electricity

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DISCLAIMERAbstract Thermophotovoltaic (TPV) devices have been fabricated using epitaxial ternary and quaternary layers grown on GaSb substrates. The GaInSb layers were grown by organometallic vapor phase epitaxy (OMVPE) and the InGaAsSb lattice-matched layers were grown by liquid phase epitaxy (LPE) . Device fabrication steps include unannealled ptype ohmic contacts, annealed Sn/Au n-type ohmic contacts, and a thick Ag topsurface contact using a lift-off process. Devices are characterized primarily by dark I-V, photo I-V, and quantum efficiency measurements, which are correlated to microscopic and macroscopic material properties. Particular emphasis has been on material enhancements to increase quantum efficiency and decrease dark saturation current density. TPV device performance is presently limited by the base diffusion length, typically 1 to 2 microns. IntroductionThis paper presents the fabrication and characterization of ternary (GaInSb) and quaternary (GaInAsSb) device layers grown on GaSb substrates, extending earlier results [l]. For current devices, all active layers have bandgaps in the 0.52eV to 0.56eV range. The lattice constants of the ternary structures are, of necessity, not matched to that of the binary (GaSb). However, the added complexity of the fourth element (As) in quaternaries allows matching the lattice constant of the epilayers to the substrate while varying the bandgap. The epitaxial growth conditions and characterization of the epitaxial material are presented elsewhere [2]. Here the fabrication and characterization of thermophotovoltaic devices using the epitaxial layers as starting material are presented. Epitaxial Structures and Junction ProcessingBoth ternary (GaInSb) and quarternary (GaInAsSb) epitaxial layers grown on GaSb substrates have been used in fabricating and characterizing p-n junctions for TPV applications. The ternary device structures were produced by OMVPE, with the quaternary device structures produced by LPE. The junctions that have been fabricated and characterized are grouped into three "generations," corresponding to the general time frame of fabrication. The ternary device structures are shown in figure 1. These generation 1 and generation 2 structures were initial structures with parameters chosen primarily based upon preliminary material studies and first-order device design. The generation 3 structure, however, contains layers with variable thicknesses and dopings in order to study the effects of individual parameter variations on device performance. In all three cases, the grown epi-layers were not lattice matched to the underlying GaSb. A series of graded layers varying from Gal.oIno.oSb at the substrate to the approximately Gao.8Ino.2Sb of the device region, separate the substrate from the base region.The quaternary device structures shown in figure 2 were fabricated by LPE. Generation 1 and 2 were identical except that generation 1 relied upon parasitic gallium anti-site defects for emitter doping, while the generation 2 emitter was doped with germanium...

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“…For n-type contacts, an evaporation of 1008, tin followed by 20008, of gold was employed [8]. In this case, the unalloyed contact was definitely non-ohmic, and an anneal was required.…”

Section: Epitaxial Structures and Junction Processingmentioning

confidence: 99%

mentioning

confidence: 99%

GaInSb and GaInAsSb thermophotovoltaic device fabrication and characterization

Hitchcock¹,

Gutmann²,

Borrego³

et al. 1997

Third NREL Conference on Thermophotovoltaic Generation of Electricity

View full text Add to dashboard Cite

show abstract

“…For n-type contacts to bulk materials, an evaporation of lOnm tin followed by 200nm of gold was employed [12], with the unalloyed contact being nonohmic. The devices were alloyed at 350°C for 5 seconds, with a resultant specific contact resistance between and Qcm2.…”

Section: Device Fabrication Techniquesmentioning

confidence: 99%

Antimonide-based devices for thermophotovoltaic applications

Hitchcock

Gutmann

Borrego

et al. 1999

IEEE Trans. Electron Devices

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“…Making a low resistance ohmic contact to n-GaSb is not trivial due to the complexity of growing a highly n-type GaSb material, difficulties in oxide removal, and a relatively undeveloped process technology. To date, ohmic contacts to n-GaSb are mainly Au-based [7][8][9][10][11][12][13][14] and Pd-based. [15][16][17][18] The first attempts at making ohmic contacts to n-GaSb were modeled on the same contact scheme used for n-GaAs.…”

mentioning

confidence: 99%

Electrical and microstructure analysis of nickel-based low-resistance ohmic contacts to n-GaSb

et al. 2013

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Ultra low resistance ohmic contacts are fabricated on n-GaSb grown by molecular beam epitaxy. Different doping concentrations and n-GaSb thicknesses are studied to understand the tunneling transport mechanism between the metal contacts and the semiconductor. Different contact metallization and anneal process windows are investigated to achieve optimal penetration depth of Au in GaSb for low resistances. The fabrication, electrical characterization, and microstructure analysis of the metal-semiconductor interfaces created during ohmic contact formation are discussed. The characterization techniques include cross-sectional transmission electron microscopy and energy dispersive spectroscopy. Specific transfer resistances down to 0.1 Ω mm and specific contact resistances of 1 × 10−6 Ω cm2 are observed.

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Ohmic contacts to p- and n-type GaSb

Cited by 31 publications

References 9 publications

GaInSb and GaInAsSb thermophotovoltaic device fabrication and characterization

GaInSb and GaInAsSb thermophotovoltaic device fabrication and characterization

Antimonide-based devices for thermophotovoltaic applications

Electrical and microstructure analysis of nickel-based low-resistance ohmic contacts to n-GaSb

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