The Influence of a TiN Cap Layer on a Titanium-S Alici de Process: Titanium vs Titanium Nitride/Titanium

1992 ◽  
Vol 260 ◽  
Author(s):  
S. -L. Zhang ◽  
W. Kaplan ◽  
M. Östling ◽  
H. Norström ◽  
A. Lindberg

To minimize the bridging problem In the self-aligned titanium slllcide (SALICI DE) processes, a titanium nitride (TiN) cap has been suggested. The objective of this work was to study the impact of such a TiN cap layer on a Ti-based SALICI DE process. The slllcide formation was carried out by Rapid Thermal Annealing (RTA). The Ti-Si Interaction, the dopant loss during silicide formation, the contact resistance between the formed TiSi2 and SI substrates, the leakage current, and the lateral diffusion of SI atoms over the spacers of MOS devices were investigated with and without a TiN layer on top of Tl films. The dependence of these factors on the annealing temperature was also investigated. The results showed that: a) An increased dopant loss was a direct result of more silicide formation, due to a larger SI substrate consumption. This was observed both with and without TiN cap. b) The specific contact resistance increased with annealing temperature, regardless the TiN cap. c) Sheet resistance, specific contact resistance and leakage current were not sensitive to the selective etch procedure. And d) A lower yield for bridging test structures was found where a TiN cap was employed, Indicating that the TiN layer did not suppress the Si lateral diffusion.

2014 ◽  
Vol 806 ◽  
pp. 57-60
Author(s):  
Nicolas Thierry-Jebali ◽  
Arthur Vo-Ha ◽  
Davy Carole ◽  
Mihai Lazar ◽  
Gabriel Ferro ◽  
...  

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.


1999 ◽  
Vol 4 (S1) ◽  
pp. 684-690
Author(s):  
X. A. Cao ◽  
F. Ren ◽  
J. R. Lothian ◽  
S. J. Pearton ◽  
C. R. Abernathy ◽  
...  

Sputter-deposited W-based contacts on p-GaN (NA∼1018 cm−3) display non-ohmic behavior independent of annealing temperature when measured at 25°C. The transition to ohmic behavior occurs above ∼250°C as more of the acceptors become ionized. The optimum annealing temperature is ∼700°C under these conditions. These contacts are much more thermally stable than the conventional Ni/Au metallization, which shows a severely degraded morphology even at 700°C. W-based contacts may be ohmic as-deposited on very heavily doped n-GaN, and the specific contact resistance improves with annealing up to ∼900°C.


1995 ◽  
Vol 395 ◽  
Author(s):  
J. Brown ◽  
J Ramer ◽  
K. ZHeng ◽  
L.F. Lester ◽  
S.D. Hersee ◽  
...  

ABSTRACTWe report on ohmic contacts to Si-implanted and un-implanted n-type GaN on sapphire. A ring shaped contact design avoids the need to isolate the contact structures by additional implantation or etching. Metal layers of Al and Ti/Al were investigated. On un-implanted GaN, post metalization annealing was performed in an RTA for 30 seconds in N2 at temperatures of 700, 800, and 900°C, A minimum specific contact resistance (rc) of 1.4×10−5 Ω-cm2 was measured for Ti/Al at an annealing temperature of 800°C. Although these values are reasonably low, variations of 95% in specific contact resistance were measured within a 500 µm distance on the wafer. These results are most likely caused by the presence of compensating hydrogen. Specific contact resistance variation was reduced from 95% to 10% by annealing at 900°C prior to metalization. On Si-implanted GaN, un-annealed ohmic contacts were formed with Ti/Al metalization. The implant activation anneal of 1120°C generates nitrogen vacancies that leave the surface heavily n-type, which makes un-annealed ohmic contacts with low contact resistivity possible.


1998 ◽  
Vol 537 ◽  
Author(s):  
X. A. Cao ◽  
F. Ren ◽  
J. R. Lothian ◽  
S. J. Pearton ◽  
C. R. Abernathy ◽  
...  

AbstractSputter-deposited W-based contacts on p-GaN (NA∼1018cm-3) display non-ohmic behavior independent of annealing temperature when measured at 25°C. The transition to ohmic behavior occurs above ∼250°C as more of the acceptors become ionized. The optimum annealing temperature is ∼700°C under these conditions. These contacts are much more thermally stable than the conventional Ni/Au metallization, which shows a severely degraded morphology even at 700°C. W-based contacts may be ohmic as-deposited on very heavily doped n-GaN, and the specific contact resistance improves with annealing up to ∼900°C.


1984 ◽  
Vol 35 ◽  
Author(s):  
S.K. Tiku ◽  
J.B. Delaney ◽  
N.S. Gabriel ◽  
H.T. Yuan

ABSTRACTA rapid thermal process for the diffusion of Zn into GaAs has been developed to fulfill the need for highly doped p type layers in GaAs technology. The process uses a solid Zn:Si:O source layer and a quartz-halogen lamp system for the thermal drive-in. Surface concentrations of the order of 1020/cm3 have been achieved with good depth reproducibility and low lateral diffusion. Specific contact resistance of Au:Zn/Au alloyed contacts fabricated using this process was in the 10−7 ohm-cm2 range.


1995 ◽  
Vol 382 ◽  
Author(s):  
Patrick W. Leec ◽  
Geoffrey K. Reeves ◽  
Wei Zhou

ABSTRACTThe specific contact resistance, pc, of Au/Zn/Au, Ni/Zn/Ni/Au, Pd/Zn/Pt/Au and Pd/Mln/Sb/Pd/Au contacts to p-In0.47Ga0.53As/ InP has been measured as a function of layer thickness of Zn or Mn. All of the as-deposited contacts were ohmic, with pc = 1−2 × 10−5 Ω cm2. Increasing thickness of the Zn layer above 200 Å in the Au/Zn/Au contacts resulted in a minor decrease in pc while producing no change in the Ni/Zn/Ni/Au metallization. For the as-deposited Pd/Mn/Pd/Au contacts, the value of pc was independent of thickness of the Mn layer but differences in pc emerged at annealing temperatures of ≥ 250°. The analysis of these structures by RBS has shown an extensive intermixing of the metal layers at an annealing temperature of 450 °. In the Pd/Zn/Pt/Au contacts, the value of pc was reduced to a minimum value of 8 × 10−6 Ω cm2 by annealing at a temperature of 500 °. An examination of the Pd/Zn/Pt/Au configuration by RBS has shown that the Pt layer acted as a barrier for the indiffusion of the Au.


1990 ◽  
Vol 181 ◽  
Author(s):  
C. Adamski ◽  
S. Meiser ◽  
D. Uffmann ◽  
L. Niewöhner ◽  
C. Schäffer

ABSTRACTThe growth of epitaxial CoSi2 by means of SPE on heavily ion implanted Si(111) was investigated with LEED, RBS and TEM. After silicide formation, the dopant distribution in silicide and silicon was determined by means of SIMS. In a self-aligned process epitaxial CoSi2/Si p+ contacts have been produced. The specific contact resistance was found to be lower than for polycrystalline CoSi2 contacts.


1990 ◽  
Vol 181 ◽  
Author(s):  
Quat T. Vu ◽  
E. Kolawa ◽  
M-A. Nicolet

ABSTRACTWe have characterized the Al/RuO2 interface after annealing at temperatures in the range 450° C-550° C for durations up to several hours by backscattering spectrometry, cross-sectional transmission electron microscopy, and electrical four point probe measurement of specially designed structures. The electrical measurement yields the specific contact resistance of the interface by applying a transmission line type model developped for this purpose. An interfacial aluminum-oxygen polycrystalline compound is shown to grow with annealing temperature and duration, with a concurrent reduction of a thin layer of RuO2. However, the specific contact resistance between Al and RuO2 is found to decrease with annealing duration at 500°C. This last result indicates that the interfacial reaction does not lead to an insulating interface as could have been expected if the growth were pure and dense A12O3.


1993 ◽  
Vol 320 ◽  
Author(s):  
Tzong-Sheng Chang ◽  
Wen-Chun Wang ◽  
Lih-Ping Wang ◽  
Jenn-Chang Hwang ◽  
Fon-Shan Huang

ABSTRACTWe have investigated TiN/TiSi2 films as diffusion barriers between copper and silicon. The TiN/TiSi2 films were formed by annealing Ti/Si via rapid thermal process at a temperature of 850'C for 30 seconds in N2 ambient. The contact resistance and leakage current of the Cu/TiN/TiSi 2/n+-p Si contact system were measured after sintering at 350-600°C for 30 minutes in an N2 ambient. We found an abrupt increase of contact resistance occurred at a sintering temperature of 600°C. From the leakage current of n+-p diode, we observed that the thermally stable temperature was about 475ycC. Meanwhile, XTEM photographs showed small Cu3Si crystallites with size of about 0.25 μm precipitated in the n+Si substrate at a sintering temperature 500°C. The formation of Cu3Si increases the occupied volume, generates the gap between TiSi2 and n+Si, and gradually increases the specific contact resistance. SIMS profiles also showed that a certain amount of Cu atoms diffused into the n+-p Si junction and that Si atoms existed in the Cu film. The Cu3Si formation across the n+-p junction can explain the abrupt increase in the leakage current measurement at 500°C. So the failure mechanisms for contact resistance and leakage current are different.


2013 ◽  
Vol 552 ◽  
pp. 162-167
Author(s):  
Min Rui Wang ◽  
Bin Yu ◽  
Yu Xia Wang

The samples of Ag/ITO multilayer films with different Ag insert layer thickness (0.5, 2, 4 nm) were prepared on sapphire and p-GaN substrates. The effects of the Ag layer thickness, annealing temperature and annealing time on the transmittance, sheet resistance and specific contact resistance of Ag/ITO films were investigated. The experiment results show that the transmittance is obviously affected by Ag insert layer thickness. The Current–voltage (I–V) measurements indicate that the sheet resistance and specific contact resistance of Ag/ITO film on p-GaN are lower than those of single ITO film. The samples with Ag(0.5nm)/ITO film on p-GaN produce the low specific contact resistance of ~1.386×10-4Ω•cm2 , low sheet resistance of ~11Ω/sq and high transmittance of ~ 90% at 455nm when the samples are annealed at 600°C for 10 minutes.


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