Piezoresistive Sensitivity and Al Ohmic Contact of Highly Doped Polycrystalline Silicon Nano Thin Films

2011 ◽  
Vol 483 ◽  
pp. 789-793
Author(s):  
Chang Zhi Shi ◽  
Xiao Wei Liu ◽  
Xuan Wu ◽  
Hai Tao Zheng
Keyword(s):  
Thin Films ◽  
Ohmic Contact ◽  
Polycrystalline Silicon ◽  
Depletion Region ◽  
Contact Resistivity ◽  
Gauge Factor ◽  
Piezoresistive Effect ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
Polycrystalline Silicon Films

The piezoresistive and ohmic contact properties of polycrystalline silicon nano thin films were investigated in this paper. The polycrystalline silicon films with different thicknesses and doping concentrations were deposited by LPCVD and doped with boron highly, and then the cantilever beam samples were fabricated by photolithography and wet etching. By measuring the gauge factor and specific contact resistivity, the specific contact resistivity of Al contacts can reach 2.4×10-3Ω·cm2 after the alloying at 450 °C for 20 min; the enhanced piezoresistive effect of highly doped polycrystalline silicon nano thin films was discovered. The conclusions indicated that the enhanced piezoresistive sensitivity of PNTFs is due to the modification of depletion region barrier by ultra high doping and film thickness thinning and the enhancement of tunneling piezoresistive effect. The distinct piezoresistive phenomenon of PNTFs could be utilized for the development and fabrication of miniature piezoresistive sensors.

Optimization of Ni/Nb Ratio for High-Temperature-Reliable Ni/Nb Silicide Ohmic Contact on 4H-SiC

2019 ◽  
Vol 963 ◽  
pp. 498-501
Author(s):  
Vuong Van Cuong ◽  
Seiji Ishikawa ◽  
Hiroshi Sezaki ◽  
Tomonori Maeda ◽  
Satoshi Yasuno ◽  
...  
Keyword(s):  
High Temperature ◽  
Ohmic Contact ◽  
Contact Resistivity ◽  
Specific Contact Resistance ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Transfer Length ◽  
Ohmic Behavior ◽  
Specific Contact ◽  
Specific Contact Resistivity

Low specific contact resistivity and high-temperature reliability of the Ni (x)/Nb (100-x) (where x = 25, 50, 75 nm) ohmic contact to 4H-SiC were investigated. After the annealing process at 1000°C for 3 min in N2 ambient, the I-V curves indicated that all the contacts exhibited the ohmic behaviors. Based on the transfer length method, the specific contact resistivity of the contacts were extracted. High concentration of Ni was responsible for low specific contact resistance of the Ni (75)/Nb (25)/4H-SiC sample by the formation of Ni2Si compound after the fabrication process. However, this contact lost the ohmic behavior at low temperature of 150°C. Whereas, both Ni (50)/Nb (50)/4H-SiC and Ni (25)/Nb (75)/4H-SiC contacts remained the ohmic behavior for 100-hour aging at 400°C. Two-dimensional X-ray diffraction analyses showed that the presence of carbon agglomeration formed at the interface of the Ni (75)/Nb (25)/4H-SiC contact caused the degradation of this sample when being aged at high temperature environment. Meanwhile, higher concentration of Nb in the Ni (50)/Nb (50)/4H-SiC and Ni (25)/Nb (75)/4H-SiC samples improved the ability to collect the excess carbon atoms and thus enhanced the high temperature reliability of these contacts when operating in high temperature ambient. Considering both low specific contact resistivity and high temperature reliability, the Ni (50)/Nb (50)/4H-SiC contact can be a good candidate for harsh environment applications.

ANNEALING EFFECTS ON CONTACT PROPERTIES OF ALUMINUM DOPED ZINC OXIDE THIN FILMS

2002 ◽  
Vol 16 (01n02) ◽  
pp. 294-301
Author(s):  
KE BIN LOW ◽  
HAO GONG ◽  
ENG FONG CHOR
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Structural Changes ◽  
Rf Magnetron Sputtering ◽  
Contact Resistivity ◽  
Glass Substrates ◽  
Specific Contact ◽  
Annealing Effects ◽  
Specific Contact Resistivity ◽  
Diffraction Patterns

Aluminum Zinc Oxide (AZO) thin films are grown on glass substrates by RF Magnetron Sputtering using a single target of zinc oxide (99 wt%) and aluminum oxide (1 wt%) with argon as the plasma. Photolithographic process is then performed on the films in order to obtain a Transmission Line Model structure (TLM) of the metal contact system, namely aluminum and gold. The specific contact resistivity, ρc, of these two metal-semiconductor systems, which will undergo different rapid thermal annealing (RTA) environment, are determined. X-Ray diffraction patterns for these samples are obtained to investigate phase formations or micro-structural changes so as to justify for the differences in specific contact resistivity obtained for these contact systems. The different RTA environment are simulated by purging either nitrogen or argon gas, with a pressure of 40 psi at a temperature of 400°C for 60 s; and annealing in vacuum (10-6 Torr) also at the same temperature and duration. One-dimensional TLM (1D-TLM) measurements are performed on the TLM structures to obtain the specific contact resistivity, ρc. Results show that aluminum contacts on AZO without RTA give the lowest ρc as compared to those in other environment, while gold contacts on AZO annealed in vacuum yield the lowest ρc. Adhesion of aluminum contacts on AZO is good even when subjected to ultrasonic bath test but not true for the case of gold contact, which adheres poorly on AZO films.

Metal/P-type GeSn Contacts with Specific Contact Resistivity down to 4.4×10−10 Ω-cm2

2018 ◽  
Author(s):  
Ying Wu ◽  
Wei Wang ◽  
Saeid Masudy-Panah ◽  
Yang Li ◽  
Kaizhen Han ◽  
...  
Keyword(s):  
Contact Resistivity ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
P Type

scholarly journals Ultralow Specific Contact Resistivity in Metal–Graphene Junctions via Contact Engineering

2018 ◽  
Vol 6 (1) ◽  
pp. 1801285 ◽  
Author(s):  
Vikram Passi ◽  
Amit Gahoi ◽  
Enrique G. Marin ◽  
Teresa Cusati ◽  
Alessandro Fortunelli ◽  
...  
Keyword(s):  
Contact Resistivity ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
Contact Engineering

scholarly journals Ar flow-rate effect for low-resistivity Al/Ti/Al Ohmic contact to n-ZnO thin films

2019 ◽  
Vol 1 (1) ◽  
pp. 23
Author(s):  
Feri Adriyanto
Keyword(s):  
Thin Films ◽  
Flow Rate ◽  
Substrate Surface ◽  
Rate Effect ◽  
Contact Resistivity ◽  
Zno Thin Films ◽  
Sputtering Power ◽  
Specific Contact ◽  
Doped Zno ◽  
Flow Rate Effect

<p class="Abstract">The Ar flow rate effect on the electrical and optical properties of the sputtered Al-doped ZnO thins films were investigated. It was shown that a strong X-ray peak from (002) and (004) planes is dominant, suggesting that most grains have <em>c</em>-axis perpendicular to the substrate surface. The (002)-ZnO and (004)-ZnO peaks were measured at 2q = 34.12<sup>0</sup>, and 71.85<sup>0</sup>, respectively. It was also found that the growth rate of the Al-doped ZnO thin films increases when the sputtering power is increased. The transmittance of these film are strongly dependent on the sputtering power with the maximum transmittance of 92% was obtained at the sputtering power of 150 W and 50 sccm of Ar flow rate. The resistivity of the films is decreases as the Ar flow rate is increased. The lowest resistivity of 9.74 x 10<sup>-4</sup> W.cm was obtained at the films with Ar flow rate of 80 sccm. The mobility increases with the Ar flow rate increases. The carrier concentration also indicates the same pattern as the mobility. The transmittance of Al-doped ZnO thin films is also strongly dependent on the Ar flow rate. It was also observed the variation of contact resistivity of Al/Ti/Al to Al-doped n-ZnO thin films. The specific contact resistivity <em>r<sub>c</sub></em> of 1.8x10<sup>−5</sup> W.cm<sup>2</sup> was obtained at 150 nm-thick Al.</p>

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