Ohmic Contact to n-GaN with TiN Diffusion Barrier

1996 ◽  
Vol 449 ◽  
Author(s):  
E. Kamińska ◽  
A. Piotrowska ◽  
M. Guziewicz ◽  
S. Kasjaniuk ◽  
A. Barcz ◽  
...  

ABSTRACTThe formation of n-GaN/Ti ohmic contacts with TiN diffusion barriers has been investigated by electrical measurements, x-ray diffraction and SIMS. It has been shown that the onset of the ohmic behaviour is associated with the thermally induced phase transformation of Ti into TiN at the GaN/Ti interface. It is suggested that the process is accompanied by an increase in the doping level in the semiconductor subcontact region. The presence of a TiN barrier is found to inhibit excessive decomposition of GaN and to confine the reaction between n-GaN and Ti.

2002 ◽  
Vol 743 ◽  
Author(s):  
C. C. Kim ◽  
P. Ruterana ◽  
J. H. Je

AbstractFor ohmic contact on p GaN, palladium is one of the best candidates showing ohmic characteristics already without annealing. To be realized in devices, it is necessary to know the behavior of the ohmic contacts at accelerated conditions, especially for high temperatures and power. We report on the structural evolution of palladium layers (30 nm) deposited on GaN (0001) by electron beam evaporation without intentional annealing. They were next cut into various pieces which were individually submitted to rapid thermal annealing at 400, 500, 600, 700 and 800°C for 10 sec. We investigate the differences in the microstructure and the location of interfacial phases and their relationships as determined by X-ray diffraction and transmission electron microscopy, we then suggest the formation mechanism based on the relationship. It is shown that the interface is disrupted at annealing above 600°C and by 800°C only very small patches of Pd are still present, however they area completely imbedded in a matrix of intermetallic phases (gallides) formed by the reaction with GaN.


1993 ◽  
Vol 300 ◽  
Author(s):  
A. Piotrowska ◽  
E. Kaminska ◽  
M. Guziewicz ◽  
S. Kwiatkowski ◽  
A. Turos

ABSTRACTThe formation of ohmic contacts to p-GaAs based on Au-Zn system comprising a TiN diffusion barrier has been investigated using 2 MeV He+ RBS and the specific contact resistance measurements. It has been proved that TiN films deposited by reactive RF bias magnetron sputtering serves two purposes. First it suppresses the arsenic evaporation and thus confines the reaction between AuZn and GaAs. Second, it prevents intermixing between p-GaAs/Au(Zn) ohmic contact and an overlayer of Au.


1999 ◽  
Vol 563 ◽  
Author(s):  
K. Y Lu ◽  
J. S. Chen

AbstractWe have studied the effect of a Ti interlayer on the behavior of a TiN diffusion barrier for Al and Cu metallizations. Thermal stability of Al/Ti/TiN/<Si> and Al/TiN/<Si> samples annealed at 400–600°C for 30 min was investigated using Auger electron spectroscopy (AES), glancing angle X-ray diffraction and scanning electron microscopy (SEM). Sheet resistance was measured for electrical characterization.After annealing at 400°C and 500°C, the AI/TiN/<Si> samples exhibited the same sheet resistance as the as-deposited one, while the sheet resistances of the Al/Ti/TiN/<Si> samples increased upon annealing. After annealing at 600°C, pyramidal pits developed on the surface of the Al/TiN/<Si> sample, but not on the Al/Ti/TiN/<Si> sample. Sheet resistance measurements for the 600°C-annealed Al/TiN/<Si> sample resulted in a more scattered distribution and a higher average value than for the Al/Ti/TiN/<Si> sample. The results clearly indicate that the performance of the TiN barrier layer is significantly improved by including a thin Ti film between the TiN and the Al. The Ti interlayer also improves the TiN barrier performance for the Cu metallization system.


Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  

This study is focused on the vibrational and microstructural aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite were annealed in static air between room temperature and 1000 °C. The kinetic of the transformation was investigated by means of thermogravimetric and differential thermal analysis, and the final product was extensively characterized via micro-Raman spectroscopy and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.


1985 ◽  
Vol 54 ◽  
Author(s):  
F. C. T. So ◽  
X.-A. Zhao ◽  
E. Kolawa ◽  
J. L. Tandon ◽  
M. F. Zhu ◽  
...  

ABSTRACTCosputtered W70Zr30 and W40Zr60 films are investigated as diffusion barriers between Al and Si. W-Zr alloys of both compositions were determined by x-ray diffraction to crystallize at 900°C on Al2O3 substrates. On <111>Si the W-Zr alloy reacts with the substrate above 700°C, forming a uniform, polycrystal line layer of W and Zr suicides. Despite the high crystallization temperatures, an Al overlayer interacts with W-Zr and the Si substrate at ∼500°C. MeV He backscattering spectrometry, SEM and EDAX indicate that this reaction is laterally nonuniform with the formation of deep pits penetrating into the Si substrate. We believe this to be a consequence of fractures in the W-Zr layer induced by reaction with Al. Electrical measurements on shallow junction diodes with <Si>/W-Zr/Al contacts show that the device junctions were thermally stable after a 30 min annealing at 450°C but were all shorted after heat treatments at 500°C or above.


2005 ◽  
Vol 483-485 ◽  
pp. 733-736 ◽  
Author(s):  
Sergio Ferrero ◽  
A. Albonico ◽  
Umberto M. Meotto ◽  
G. Rambolà ◽  
Samuele Porro ◽  
...  

In this work we report an analysis on Ni/4H-SiC interfaces aimed at optimizing the ohmic contacts. Several thermal cycles have been performed by rapid thermal annealing checking the possible chemical reactions at the metal semiconductor interfaces. Micro x-ray diffraction and micro Raman techniques have been performed in order to study the interface micro structural evolution. Inter diffusion of each element at the Ni - SiC interface was examined using Auger spectroscopy. Electrical measurements have been performed in order to check the ohmic behavior of the contacts. Finally, a correlation between microstructures evolution and electrical behaviors is reported.


1993 ◽  
Vol 300 ◽  
Author(s):  
E. Kamińska ◽  
A. Piotrowska ◽  
E. Mizera ◽  
R. Zarecka ◽  
J. Adamczewska ◽  
...  

ABSTRACTThe reactions between (100) GaAs and Au, Zn, and Au(Zn) ohmic contact metallization have been investigated by the use of transmission electron microscopy and x-ray diffraction. Emphasis is placed on the particular role of Zn during consecutive stages of the formation of an ohmic contact to p-GaAs. The most significant feature of the interaction of Zn with GaAs is the penetration of Zn atoms into the native oxide, which remains at the surface of GaAs after chemical treatment. Moreover, the presence of Zn in Au-based metallization is found to considerably suppress the thermally induced growth of metallization grains, making the microstructure of the contact virtually intact upon annealing at temperatures up to 460°C.


1990 ◽  
Vol 181 ◽  
Author(s):  
E. Kolawa ◽  
L. Halperin ◽  
P. Pokela ◽  
Quat T Vu ◽  
C. W. Nieh

ABSTRACTThin films of amorphous TiP and TiPN2 alloys were deposited by sputtering of a TiP target in an Ar and N2/Ar mixture, respectively. These alloy films were tested as diffusion barriers between Al and Si as well as between Cu and Si and also in metallizations which included TiSi2 as the contacting layer. Rutherford backscattering spectrometry, x-ray diffraction and electrical measurements were used to determine the barrier effectiveness. We find that TiP and TiPN2 films prevent the interdiffusion and reaction between Al and Si up to 500°C and 600°C for 30 minutes annealing, respectively, and between Cu and Si up to 600°C and 700°C, respectively.


Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  

This study deals with vibrational and crystallographic aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite have been annealed in static air between room temperature and 1000 °C. The resulting products from the transformations detected based on thermogravimetric and differential thermal analysis, have been extensively characterized via microRaman spectroscopy, and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.


2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.


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