Process Design for Non-Alloyed Contacts to InP-Based Laser Devices

1990 ◽  
Vol 181 ◽  
Author(s):  
A. Katz ◽  
W. C. Dautremont-Smith ◽  
S. N. G. Chu ◽  
S. J. Pearton ◽  
M. Geva ◽  
...  
Keyword(s):  
Process Design ◽  
Ohmic Contacts ◽  
Electron Gun ◽  
Deposition Parameters ◽  
Heat Treated ◽  
Single Side ◽  
Almost All ◽  
P Type ◽  
Laser Devices ◽  
Potential Use

ABSTRACTPl/Ti and W thin films on n- and p- type InP and related materials have been investigated for potential use as a refractory ohmic contacts for conventional, single-side coplanar contacted and self-aligned barrier hetcrostructurc laser devices. Pt and Ti films were deposited sequentially by electron gun evaporation, while the W layer was rf sputtered, both onto p+ -In0.53Ga0.47As (Zn doped 5×l018cm−3) and n−- InP (S doped, 5×l018cm−3). The deposition parameters of the two metal systems were optimized to produce adherent films with the lowest possible induced stress. Almost all the studied systems performed as ohmic contacts already as-deposited and were heat treated by means of rapid thermal processing in the temperature range of 300–900°C. The final contact processing conditions were tuned to provide the lowest possible contact resistance values accompanied by low mechanical stress and stable microstructure.

A Comparative Study of MOCVD Produced ZnO Films Doped with N, As, P and Sb

2006 ◽  
Vol 957 ◽  
Author(s):  
Gary S. Tompa ◽  
S. Sun ◽  
C. E. Rice ◽  
L. G. Provost ◽  
D. Mentel
Keyword(s):  
Thin Films ◽  
Comparative Study ◽  
Ohmic Contacts ◽  
Zno Thin Films ◽  
Zno Films ◽  
Electrical Measurements ◽  
Light Emitters ◽  
Hall Measurements ◽  
Deposition Parameters ◽  
P Type

ABSTRACTZnO thin films are of interest for an array of applications; including: light emitters, photovoltaics, sensors and transparent contacts among others. Of particular interest is the potential to produce p-type layers from which p-n junction devices could be routinely produced. While it is fairly routine for MOCVD to produce n-type films with doping concentrations in the 10E20 cm-3 range and resistivities below 10E-3 ohm-cm; it is very difficult to produce measurable p-type ZnO. We report on our efforts with doping films p-type using N gas sources and metalorganic sources of P, As, and Sb. Films showing acceptor bands by photoluminescence have been demonstrated; however reliable electrical measurements remain difficult. Specific problems include achieving low resistance ohmic contacts, accounting for the photo-responsiveness of ZnO films and sensitivity limits in Hall measurements of low-doped and compensated materials. The presentation will review deposition parameters, produced and processed films and material characteristics.

Effect of Silver Content on the Crystalline Phase and Microstructure of TiO2 Coating Deposited on Unglazed Ceramics Tile

2020 ◽  
Vol 17 (3) ◽  
pp. 8179-8185
Author(s):  
N.Z. Hafizah ◽  
J. M. Juoi ◽  
M.R. Zulkifli ◽  
M.A. Musa
Keyword(s):  
Particle Growth ◽  
Dip Coating ◽  
Tio2 Coating ◽  
High Concentration ◽  
Ceramic Tiles ◽  
Soaking Time ◽  
Heat Treated ◽  
Ag Particles ◽  
Tio2 Sol ◽  
Almost All

The synthesis of Ag-TiO2 coating using AgNO3 precursor is expected to give the properties as pure as Ag nanoparticles. Commonly, high concentration of Ag attributed to agglomeration of silver species and reduction to Ag0 particles on TiO2 surface. In contrast, at lower concentration, Ag species exist as AgO, Ag2O and Ag0. Hence, the exact amount of Ag, which can effectively control the particle growth and agglomeration, surface area, thermal stability and band gap of the TiO2 coating, are still vague and stated differently. In the present study, the effect of Ag content on the phase transformation and surface morphology of Ag-TiO2 coating were reported. TiO2 sol were prepared by incorporating Ag at 2.5, 5 and 7.5 mol % and deposited on unglazed ceramic tiles thru five times dip coating. The deposited Ag-TiO2 coatings were heat treated at 500 °C for 1 hour soaking time. XRD analyses revealed that the deposited Ag-TiO2 coating consists of anatase, rutile, Ag2O and metallic Ag. Almost all the coating surfaces illustrated cracks. Increased Ag content lead to presence of tiny particles on the surfaces and EDX spectrum revealed the presence of Ti, O and metallic Ag particles. However, at the addition of 5 mol % Ag, there was no metallic Ag presence and a dense coating with the lowest thickness of ±11.4µm is observed.

Spectrum of Defect States in Porous Organic Low-k Dielectric Films, Annealed in Argon and Nitrogen

2003 ◽  
Vol 766 ◽  
Author(s):  
V. Ligatchev ◽  
T.K.S. Wong ◽  
T.K. Goh ◽  
Rusli Suzhu Yu
Keyword(s):  
Deep Level ◽  
Dielectric Films ◽  
Silicon Substrates ◽  
Reverse Bias Voltage ◽  
Defect States ◽  
Single Side ◽  
Sandwich Type ◽  
Transient Spectroscopy ◽  
P Type ◽  
Spectrum Deconvolution

AbstractDefect spectrum N(E) of porous organic dielectric (POD) films is studied with capacitance deep-level-transient-spectroscopy (C-DLTS) in the energy range up to 0.7 eV below conduction band bottom Ec. The POD films were prepared by spin coating onto 200mm p-type (1 – 10 Δcm) single-side polished silicon substrates followed by baking at 325°C on a hot plate and curing at 425°C in furnace. The film thickness is in the 5000 – 6000 Å range. The ‘sandwich’ -type NiCr/POD/p-Si/NiCr test structures showed both rectifying DC current-voltage characteristics and linear 1/C2 vs. DC reverse bias voltage. These confirm the applicability of the C-DLTS technique for defect spectrum deconvolution and the n-type conductivity of the studied films. Isochronal annealing (30 min in argon or 60 min in nitrogen) has been performed over the temperature range 300°C - 650°C. The N(E) distribution is only slightly affected by annealing in argon. However, the distribution depends strongly on the annealing temperature in nitrogen ambient. A strong N(E) peak at Ec – E = 0.55 – 0.60 eV is detected in all samples annealed in argon but this peak is practically absent in samples annealed in nitrogen at Ta < 480°C. On the other hand, two new peaks at Ec – E = 0.12 and 0.20 eV appear in the N(E) spectrum of the samples annealed in nitrogen at Ta = 650°C. The different features of the defect spectrum are attributed to different interactions of argon and nitrogen with dangling carbon bonds on the intra-pore surfaces.

Adsorption of Carbon Monoxide on Pd/SiO2/Si(111) Studied by Core-Level Photoemission

1998 ◽  
Vol 63 (11) ◽  
pp. 1793-1802 ◽  
Author(s):  
Zdeněk Bastl ◽  
Tomáš Šarapatka
Keyword(s):  
Carbon Monoxide ◽  
Photoelectron Spectroscopy ◽  
Co Adsorption ◽  
Charge Balance ◽  
Adsorption Activity ◽  
Chemical States ◽  
Adsorbed Co ◽  
Pd Clusters ◽  
Almost All ◽  
P Type

X-Ray photoelectron spectroscopy (XPS) has been used to study the adsorption of carbon monoxide on Pd dispersed on oxidized Si(111) surface. A fraction of the deposited Pd diffusing at room temperature to the SiO2/Si interface increases with decreasing SiO2 thickness. For oxide layers thinner than ≈1 nm, almost all deposited Pd diffuses to SiO2/Si interface forming there Si silicide. Consequently, the amount of adsorbed CO is dependent on the thickness of the thermally grown SiO2 layer. Two different chemical states of adsorbed carbon atoms, the population of which depends on the amount of the Pd deposited, are observed in the C (1s) spectra of adsorbed CO. Adsorption activity of Pd clusters does not depend on whether n- or p-type Si is used. Comparison of the experimental Pd/CO concentration ratios with those calculated assuming several different modes of the Pd growth on SiO2/Si points to the pseudo-Stranski-Krastanow mode (flat clusters with incomplete condensation of the first layer) at 300 K. Changes in charge balance across the Pd/SiO2/Si interface caused by CO adsorption are discussed in terms of the surface photovoltage effect and work function variation.

Thermodynamics and Microstructure Development in the Thin Film Reaction of Aluminum on Silicon Carbide

1995 ◽  
Vol 403 ◽  
Author(s):  
T. S. Hayes ◽  
F. T. Ray ◽  
K. P. Trumble ◽  
E. P. Kvam
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Silicon Carbide ◽  
Ohmic Contacts ◽  
Microstructure Development ◽  
P Type ◽  
Microstructural Studies

AbstractA refined thernodynamic analysis of the reaction between molen Al and SiC is presented. The calculations indicate much higher Si concentrations for saturation with respect to AkC 3 formation than previously reported. Preliminary microstructural studies confirm the formation of interfacial A14C3 for pure Al thin films on SiC reacted at 9000C. The implications of the calculations and experimental observations for the production of ohmic contacts to p-type SiC are discussed.

Correlation between the electrical properties and the interfacial microstructures of TiAl-based ohmic contacts to p-type 4H-SiC

2004 ◽  
Vol 33 (5) ◽  
pp. 460-466 ◽  
Author(s):  
S. Tsukimoto ◽  
K. Nitta ◽  
T. Sakai ◽  
M. Moriyama ◽  
Masanori Murakami
Keyword(s):  
Electrical Properties ◽  
Ohmic Contacts ◽  
P Type

Improvement of the Specific Contact Resistance on P-Type 4H-SiC by Using a Highly P-Typed Doped 4H-SiC Layer Selectively Grown by VLS Transport

2014 ◽  
Vol 806 ◽  
pp. 57-60
Author(s):  
Nicolas Thierry-Jebali ◽  
Arthur Vo-Ha ◽  
Davy Carole ◽  
Mihai Lazar ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Schottky Barrier Height ◽  
Annealing Temperature ◽  
Process Condition ◽  
Specific Contact Resistance ◽  
High Doping Level ◽  
Annealing Temperatures ◽  
Specific Contact ◽  
P Type

This work reports on the improvement of ohmic contacts made on heavily p-type doped 4H-SiC epitaxial layer selectively grown by Vapor-Liquid-Solid (VLS) transport. Even before any annealing process, the contact is ohmic. This behavior can be explained by the high doping level of the VLS layer (Al concentration > 1020 cm-3) as characterized by SIMS profiling. Upon variation of annealing temperatures, a minimum value of the Specific Contact Resistance (SCR) down to 1.3x10-6 Ω.cm2 has been obtained for both 500 °C and 800 °C annealing temperature. However, a large variation of the SCR was observed for a same process condition. This variation is mainly attributed to a variation of the Schottky Barrier Height.

Selective Area Deposition of Passivants, Insulators, and Epitaxial Films of II-VI Compound Semiconductors

1989 ◽  
Vol 161 ◽  
Author(s):  
D.L. Dreifus ◽  
Y. Lansari ◽  
J.W. Han ◽  
S. Hwang ◽  
J.W. Cook ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Epitaxial Films ◽  
Semiconductor Surface ◽  
Epitaxial Layers ◽  
Double Crystal ◽  
Surface Areas ◽  
Selective Area ◽  
Lift Off ◽  
P Type ◽  
Area Deposition

ABSTRACTII-VI semiconductor surface passivants, insulators, and epitaxial films have been deposited onto selective surface areas by employing a new masking and lift-off technique. The II-VI layers were grown by either conventional or photoassisted molecular beam epitaxy (MBE). CdTe has been selectively deposited onto HgCdTe epitaxial layers as a surface passivant. Selective-area deposition of ZnS has been used in metal-insulator-semiconductor (MIS) structures. Low resistance ohmic contacts to p-type CdTe:As have also been realized through the use of selectively-placed thin films of the semi-metal HgTe followed by a thermal evaporation of In. Epitaxial layers of HgTe, HgCdTe, and HgTe-CdTe superlattices have also been grown in selective areas on CdZnTe substrates, exhibiting specular morphologies and double-crystal x-ray diffraction rocking curves (DCXD) with full widths at half maximum (FWHMs) as narrow as 140 arcseconds.

The Effect of Heat Treatment on Ni/Au Ohmic Contacts to p-Type GaN

1999 ◽  
Vol 176 (1) ◽  
pp. 773-777 ◽  
Author(s):  
Li-Chien Chen ◽  
Jin-Kuo Ho ◽  
Fu-Rong Chen ◽  
Ji-Jung Kai ◽  
Li Chang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Ohmic Contacts ◽  
P Type

LIGHT-INDUCED EXCESS CONDUCTIVITY AND THE ROLE OF ARGON IN THE DEPOSITION OF DOPING-MODULATED AMORPHOUS SILICON SUPERLATTICES.

1985 ◽  
Vol 56 ◽  
Author(s):  
F.-C. Su ◽  
S. Levine ◽  
P. E. Vanier ◽  
F. J. Kampas
Keyword(s):  
Amorphous Silicon ◽  
Amorphous Semiconductor ◽  
Excess Conductivity ◽  
The Novel ◽  
Semiconductor Superlattice ◽  
Deposition Parameters ◽  
Superlattice Structures ◽  
Argon Dilution ◽  
P Type

AbstractAmorphous semiconductor superlattice structures consisting of alternating n-type and p-type doped layers of hydrogenated amorphous silicon (a-Si:H) have been made by silane glow discharge in a single chamber system. These multilayered films show the novel phenomenon of light-induced excess conductivity (LEC) associated with a metastable state having a lifetime of order of days. This report shows that the LEC effect is quite dependent on the specific details of the deposition parameters, namely dilution of the silane with inert gas, substrate temperature and layer thickness. In order to investigate the origin of the LEC effect, argon dilution was used for specific regions of the structure. This experiment shows that the slow states are distributed throughout the layers, and are not concentrated at the interfaces.

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