scholarly journals Постростовые технологии каскадных фотоэлектрических преобразователей на основе A-=SUP=-3-=/SUP=-B-=SUP=-5-=/SUP=--гетероструктур

2022 ◽  
Vol 92 (1) ◽  
pp. 108
Author(s):  
А.В. Малевская ◽  
Н.Д. Ильинская ◽  
Ю.М. Задиранов ◽  
А.А. Блохин ◽  
Д.А. Малевский ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Ion Beam ◽  
Surface Current ◽  
Contact Layer ◽  
Antireflection Coating ◽  
Ion Beam Etching ◽  
Mesa Structure ◽  
Structure Surface ◽  
P Type ◽  
Growth Technology

Investigation and development of the post-growth technology for fabricating multi-junction photovoltaic converters based on GaInP/GaInAs/Ge heterostructure has been carried out. Antireflection coating, ohmic contacts and mesa-structure forming stages have been reviewed. The technology of n+-GaAs contact layer etching with the help of plasma-chemical, liquid and ion-beam etching has been investigated. Antireflection coefficient of radiation from the heterostructure with TiOx/SiO2 (x close to 2) antireflection coating surface was less then 3% in wavelength range 450-850 nm. The value of contact resistance for n- and p-type conductivity was 3E−5 − 3E−6 ohm · cm2, the decrease of photosensitive region shading degree at increased bus-bar conductivity has been archived. The mesa-structure surface current leakage decreased to the value of E-9 A at voltage less then 1 V.

Reliability of Ohmic Contacts for AlGaAs/GaAs HBTs

1990 ◽  
Vol 184 ◽  
Author(s):  
G. S. Jackson ◽  
E. Tong ◽  
P. Saledas ◽  
T. E. Kazior ◽  
R. Sprague ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Contact Resistance ◽  
Ohmic Contacts ◽  
Ion Beam ◽  
Sintering Process ◽  
Electrical Stability ◽  
Long Term Stability ◽  
Heavily Doped ◽  
P Type

ABSTRACTThe reliability of ohmic contacts to thin, heavily doped layers of GaAs is investigated. Pd/Ge/Au contacts to n-type GaAs display excellent electrical stability over extended periods of thermal stress. The contact resistance stays below 0.50Ω-mim during a 2500h, 280°C bake. Reactive ion beam assisted evaporation of Ti with N forms TiN which is introduced as a barrier layer in Pt/TiN/Ti/Au contacts to a thin p+ layer. The TiN layer allows greater process latitude in the sintering process and improves long term stability of the ohmic contact. The microstructure of the p-type contacts is examined with TEM and Auger profiling at different instances of the 2500h, 280°C bake and compared to the contact resistance measurements.

Transport Mechanisms in Focused Ion Beam Assisted Ohmic Contacts to p-Type 6H-SiC

2002 ◽  
Vol 742 ◽  
Author(s):  
Agis A. Iliadis
Keyword(s):  
Transport Mechanism ◽  
Ohmic Contacts ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Direct Write ◽  
Current Transport ◽  
Semiconductor Interface ◽  
Current Transport Mechanism ◽  
Surface Modified ◽  
P Type

ABSTRACTThe current transport mechanism in non-annealed Ohmic contact metallizations on p-type 6H-SiC formed by using focused ion beam (FIB) surface-modification and direct-write metal deposition is reported, and the properties of such focused ion beam assisted non-annealed contacts are discussed. The process uses a Ga focused ion beam to modify the surface of the semiconductor with different doses, and then introduces an organometallic compound in the Ga ion beam, to effect the direct-write deposition of a metal on the modified surface. Contact resistance measurements by the transmission line method produced values in the low 10-4 Ω cm2 range for surface-modified and direct-write Pt and W non-annealed contacts, and mid 10-5 Ω cm2 range for surface-modified and pulse laser deposited TiN contacts. The current transport mechanism of these contacts was examined and found to proceed mainly by tunneling through the metal-modified-semiconductor interface layer.

Ti/AlNi/W and Ti/Ni2Si/W Ohmic Contacts to P-Type SiC

2006 ◽  
Vol 527-529 ◽  
pp. 903-906 ◽  
Author(s):  
Bang Hung Tsao ◽  
Jacob Lawson ◽  
James D. Scofield
Keyword(s):  
Ohmic Contacts ◽  
High Vacuum ◽  
Surface Region ◽  
Contact Layer ◽  
Ohmic Behavior ◽  
Specific Contact ◽  
Main Observation ◽  
The Stability ◽  
P Type ◽  
Contact Resistivities

AlNi and Ni2Si based ohmic contacts to p-type 4H-SiC have been produced using low energy ion implantation, a Ti contact layer, and sequential anneals. Low resistivities were promoted by degenerately (>1020 cm-3) doping the surface region of 4H-SiC epilayers via Al+ implantation. High acceptor activation and improved surface morphology was achieved by capping the samples with pyrolized photoresist and using a two-step anneal sequence in argon. Ti/AlNi/W and Ti/Ni2Si/W stacks of varying Ti and/or binary layer thickness were compared at varying anneal temperatures. AlNi based samples reliably and repeatedly achieved specific contact resistivities as low as 5.5 x10-5 ohm-cm2 after annealing at temperatures of 700-1000°C. For the Ni2Si samples, resistivities as low 4.5x10-4 ohm-cm2 were reached after annealing between 750 and 1100°C. Similarly, a set of Ti/AlNi/Au samples, with or without Ge as an additional contact layer, were prepared via the same procedures. In this case, specific contact resistivities as low as 5.0 x10-4 ohm-cm2 were achieved after annealing the Ti/AlNi/Au samples between 600 and 700°C for 30 minutes in a dynamic argon atmosphere or under high vacuum. The lowest resistivities were realized using thicker (~ 40 nm) Ti layers. I-V analysis revealed superior linear characteristics for the AlNi system, which also exhibited a more stable microstructure after anneal. SIMS and RBS were used to analyze the stability of the stacks subsequent to thermal treatment. AFM analysis demonstrated the superiority of photoresist capping over alternatives in minimizing surface roughness. Linear ohmic behavior after significantly reduced anneal temperature is the main observation of the present study.

Reliability of Ohmic Contacts for AlGaAs/GaAs HBTs

1990 ◽  
Vol 181 ◽  
Author(s):  
G. S. Jackson ◽  
E. Tong ◽  
P. Saledas ◽  
T. E. Kazior ◽  
R. Sprague ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Contact Resistance ◽  
Ohmic Contacts ◽  
Ion Beam ◽  
Sintering Process ◽  
Electrical Stability ◽  
Long Term Stability ◽  
Heavily Doped ◽  
P Type

ABSTRACTThe reliability of ohmic contacts to thin, heavily doped layers of GaAs is investigated. Pd/Ge/Au contacts to n-type GaAs display excellent electrical stability over extended periods of thermal stress. The contact resistance stays below 0.5Ω-mm during a 2500h, 280°C bake. Reactive ion beam assisted evaporation of Ti with N forms TiN which is introduced as a barrier layer in Pt/TiN/Ti/Au contacts to a thin p+ layer. The TiN layer allows greater process latitude in the sintering process and improves long term stability of the ohmic contact. The microstructure of the p-type contacts is examined with TEM and Auger profiling at different instances of the 2500h, 280°C bake and compared to the contact resistance measurements.

Pt:Ti Diffusion Barrier, Interconnect, and Simultaneous Ohmic Contacts to n- and p-Type 4H-SiC

2018 ◽  
Vol 924 ◽  
pp. 381-384 ◽  
Author(s):  
Robert S. Okojie ◽  
Dorothy Lukco
Keyword(s):  
Diffusion Barrier ◽  
Ohmic Contacts ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specific Contact Resistance ◽  
Long Term Stability ◽  
Specific Contact ◽  
P Type ◽  
Fabrication Costs

We report the initial results of using co-sputtered Pt:Ti 80:20 at. % composition ratio metallization as a diffusion barrier against gold (Au) and oxygen (O), as an interconnect layer, as well as forming simultaneous ohmic contacts to n-and p-type 4H-SiC. Having a single conductor with such combined multi-functional attributes would appreciably reduce the fabrication costs, processing time and complexity that are inherent in the production of SiC based devices. Auger Electron Spectroscopy, Focused Ion Beam-assisted Field Emission Scanning Electron Microscopy and Energy Dispersive Spectroscopy analyses revealed no Au and O migration to the SiC contact surface and minimal diffusion through the Pt:Ti barrier layer after 15 minutes of exposure at 800 oC in atmosphere, thus offering potential long term stability of the ohmic contacts. Specific contact resistance values of 7 x 10-5 and 7.4 x 10-4 Ω-cm2 were obtained on the n (Nd=7 x 1018 cm-3) and p (Na=2 x 1020 cm-3) -type 4H-SiC, respectively. The resistivity of 75 μΩ-cm was obtained for the Pt:Ti layer that was sandwiched between two SiO2 layers and annealed in pure O ambient up to 900 °C, which offers promise as a high temperature interconnect metallization.

The thickness correction of sol-gel coating using ion-beam etching in the preparation of antireflection coating

2017 ◽  
Author(s):  
Siyu Dong ◽  
Lingyun Xie ◽  
Hongfei Jiao ◽  
Jinlong Zhang ◽  
Zhanshan Wang ◽  
...  
Keyword(s):  
Ion Beam ◽  
Sol Gel ◽  
Antireflection Coating ◽  
Ion Beam Etching ◽  
Thickness Correction

scholarly journals Исследование формирования антиотражающего покрытия каскадных солнечных элементов

2019 ◽  
Vol 45 (20) ◽  
pp. 15
Author(s):  
А.В. Малевская ◽  
Ю.М. Задиранов ◽  
А.А. Блохин ◽  
В.М. Андреев
Keyword(s):  
Solar Cells ◽  
Reflection Coefficient ◽  
Ion Beam ◽  
Antireflection Coating ◽  
Plasma Chemical ◽  
Ion Beam Etching ◽  
Coating Adhesion ◽  
Multijunction Solar Cells ◽  
Liquid Chemical

Investigations of antireflection coating creating for multijunction solar cells based on AIIIBV heterostructures have been carried out. Investigated were modes of treatment of a heterostructure surface with application of plasma-chemical, liquid chemical and ion-beam etching methods. Technology for creating antireflection coating based on ТiOx/SiO2 layers was developed. Improvement of parameters of coating adhesion to the heterostructure surface and reduction of the reflection coefficient in multijunction solar cells were achieved.

Simultaneous Formation of n- and p-Type Ohmic Contacts to 4H-SiC Using the Binary Ni/Al System

2008 ◽  
Vol 1069 ◽  
Author(s):  
Kazuhiro Ito ◽  
Toshitake Onishi ◽  
Hidehisa Takeda ◽  
Susumu Tsukimoto ◽  
Mitsuru Konno ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Ohmic Contacts ◽  
Field Effect Transistors ◽  
High Vacuum ◽  
Contact Layer ◽  
Ultra High Vacuum ◽  
Oxide Semiconductor ◽  
Simultaneous Formation ◽  
Ohmic Behavior ◽  
P Type

ABSTRACTFabrication procedure for silicon carbide power metal oxide semiconductor field effect transistors can be improved through simultaneous formation of ohmic contacts on both the n-source and p-well regions. We have succeeded in the simultaneous formation of Ni/Al ohmic contacts to n- and p-type SiC after annealing at 1000°C for 5 mins in an ultra-high vacuum. Ohmic contacts to n-type SiC were found when Al-layer thickness was less than about 5 nm while ohmic contacts to p-type SiC were observed for an Al-layer thickness greater than about 5 nm. Only the contacts with Al-layer thicknesses in the range of 5 to 6 nm exhibited ohmic behavior to both n- and p-type SiC, with specific contact resistances of 1.8 × 10−4 Ωcm2 and 1.2 × 10−2 Ωcm2 for n- and p-type SiC, respectively. An about 100 nm-thick contact layer was uniformly formed on the SiC substrate and polycrystalline δ-Ni2Si(Al) grains were formed at the contact/SiC interface. The distribution in values for the Al/Ni ratio in the δ-Ni2Si(Al) grains which exhibited ohmic behavior to both n- and p-type SiC was the largest. The smallest average δ-Ni2Si(Al) grain size was also observed in these contacts. Thus, the large distribution in the Al/Ni ratios and a fine microstructure were found to be characteristic of the ohmic contacts to both n- and p-type SiC.

Ultrastructural Features of Normal and Diseased Hair Revealed by Ion Beam Etching and Freeze Fracture

1975 ◽  
Vol 33 ◽  
pp. 358-359
Author(s):  
M. Spector ◽  
A. C. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ectodermal Dysplasia ◽  
Ion Beam ◽  
Freeze Fracture ◽  
Ion Current ◽  
Ion Beam Etching ◽  
Pili Torti ◽  
Argon Ion ◽  
Scanning Electron

Ion beam etching and freeze fracture techniques were utilized in conjunction with scanning electron microscopy to study the ultrastructure of normal and diseased human hair. Topographical differences in the cuticular scale of normal and diseased hair were demonstrated in previous scanning electron microscope studies. In the present study, ion beam etching and freeze fracture techniques were utilized to reveal subsurface ultrastructural features of the cuticle and cortex.Samples of normal and diseased hair including monilethrix, pili torti, pili annulati, and hidrotic ectodermal dysplasia were cut from areas near the base of the hair. In preparation for ion beam etching, untreated hairs were mounted on conducting tape on a conducting silicon substrate. The hairs were ion beam etched by an 18 ky argon ion beam (5μA ion current) from an ETEC ion beam etching device. The ion beam was oriented perpendicular to the substrate. The specimen remained stationary in the beam for exposures of 6 to 8 minutes.

Chemical Precursors for GaAs Etching with low Energy ion Beams: Chlorine adsorption on GaAs(100)

1991 ◽  
Vol 223 ◽  
Author(s):  
Richard B. Jackman ◽  
Glenn C. Tyrrell ◽  
Duncan Marshall ◽  
Catherine L. French ◽  
John S. Foord
Keyword(s):  
Ion Beam ◽  
Ion Beams ◽  
Low Energy ◽  
Ion Beam Etching ◽  
Chlorine Adsorption

ABSTRACTThis paper addresses the issue of chlorine adsorption on GaAs(100) with respect to the mechanisms of thermal and ion-enhanced etching. The use of halogenated precursors eg. dichloroethane is also discussed in regard to chemically assisted ion beam etching (CAIBE).

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