I-V Characteristics and Interface Properties of Al-Si(P) Contacts by the Krf Excimer Laser Induced Recrystallization

1992 ◽  
Vol 283 ◽  
Author(s):  
K. Sohn ◽  
H. Lee ◽  
D. A. Hensley
Keyword(s):  
Excimer Laser ◽  
Ohmic Contacts ◽  
Schottky Diodes ◽  
Interface Properties ◽  
Auger Analysis ◽  
Effective Barrier ◽  
Thermionic Field Emission ◽  
Krf Excimer Laser ◽  
The One ◽  
P Type

ABSTRACTAl was deposited on the both sides of p-type Si by the sputtering, and the pulsed KrF excimer laser was irradiated on the one side and both sides of Al dot contacts. Due to the thin-high doping recrystallized layer, the transitions from the Schottky diodes to the ohmic contacts via backward diodes were observed in I-V measurement. Good N-shape negative resistances and notches were observed in the diodes, and ohmic contacts. Possible interpretations of the orgin of these phenomena are discussed. And, the simple model of the effective barrier height reduction under the thermionic field emission was developed using WKB approximation, and tunneling theory. By the depth Auger analysis, Al, and Si profiles near Al-Si interface after the laser irradiation were observed.

Stable Low Resistance Ohmic Contacts To p-GaN

2001 ◽  
Vol 680 ◽  
Author(s):  
Mi-Ran Park ◽  
Wayne A. Anderson
Keyword(s):  
Contact Resistance ◽  
Photoelectron Spectroscopy ◽  
Ohmic Contacts ◽  
Depth Profiling ◽  
Force Microscopy ◽  
Low Resistance ◽  
Atomic Force ◽  
Current Voltage ◽  
Thermionic Field Emission ◽  
P Type

ABSTRACTStable and low-resistance Ohmic contacts are especially important for laser diodes where high current levels are required. Good contacts are especially difficult on p-type GaN which was the motivation for this study. The GaN was epitaxially grown on (0001) sapphire substrates by MOCVD. Resistivity of this layer was 3.5 Ohm-cm and thickness was 2 microns. After conventional cleaning followed by treatment in boiling HNO3: HCl (1:3), metallization was by thermally evaporating 40 nm Au / 60 nm Ni or 70 nm Au / 55 nm Pd. Heat treatment in O2 + N2 at various temperatures followed, with best results at 600 °C or 700 °C, respectively. Best values of the contact resistance were 1.8×10−4 Ohm-cm2 for Pd/Au and 2.65×10−4 Ohm-cm2 for Ni/Au contacts. After repetitive cycling from room temperature to 600 °C, the Ni contacts were very stable and more stable than the Pd contacts. X-ray photoelectron spectroscopy depth profiling showed the Ni contacts to be NiO followed by Au at the interface for the Ni/Au contacts whereas the Pd/Au contacts exhibited a Pd: Au solid solution. Some contacts were quenched in liquid nitrogen following sintering. These contacts were much more uniform under atomic force microscopy examination and gave a 3 times lower contact resistance with the Ni/Au design. Current-voltage-temperature analysis revealed that conduction was predominantly by thermionic field emission.

High Quality Non-Alloyed Pt Ohmic Contacts to P-Type GaN Using Two-Step Surface Treatment

1999 ◽  
Vol 595 ◽  
Author(s):  
Ja-Soon Jang ◽  
Seong-Ju Park ◽  
Tae-Yeon Seong
Keyword(s):  
Surface Treatment ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Transport Mechanisms ◽  
High Quality ◽  
Ammonium Sulfide ◽  
Current Voltage ◽  
Specific Contact ◽  
Thermionic Field Emission ◽  
P Type

AbstractTwo-step surface-treatment is introduced to obtain low resistance Pt contacts to ptype GaN. The first step is performed after the mesa etching process using buffered oxide etch (BOE) and ammonium sulfide [(NH4)2Sx]. This is followed by the second step using BOE. The Pt contact, which was treated sequentially using ultrasonically boiled BOE (10 min) and boiled (NH4)2Sx (10 min), produces a specific contact resistance of 3.0 (±3.8)×10-5 Ωcm2. However, the contact, that was simply BOE-treated, yields 3.1 (±1.1)×10-2 Ωcm2. This indicates that the two-step surface treatment is promising technique for obtaining high quality ohmic contacts to p-GaN. Investigation of the electronic transport mechanisms using current-voltage-temperature (I-V-T) data indicates that thermionic field emission is dominant in the surface-treated Pt contacts.

Low resistance nonalloyed Ni∕Au Ohmic contacts to p-GaN irradiated by KrF excimer laser

2006 ◽  
Vol 89 (4) ◽  
pp. 042107 ◽  
Author(s):  
Min-Suk Oh ◽  
Dae-Kue Hwang ◽  
Jae-Hong Lim ◽  
Chang-Goo Kang ◽  
Seong-Ju Park
Keyword(s):  
Excimer Laser ◽  
Ohmic Contacts ◽  
Low Resistance ◽  
Krf Excimer Laser

scholarly journals Contact resistivity of Al/Ti ohmic contacts on p-type ion implanted 4H- and 6H-SiC.

2002 ◽  
Vol 742 ◽  
Author(s):  
Roberta Nipoti ◽  
Francesco Moscatelli ◽  
Andrea Scorzoni ◽  
Antonella Poggi ◽  
Gian Carlo Cardinali ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Contact Resistivity ◽  
Current Crowding ◽  
Wafer Level ◽  
Limit Value ◽  
Thermionic Field Emission ◽  
Increasing Temperature ◽  
P Type ◽  
Maximum Contact ◽  
Ion Implanted

ABSTRACTAl-Ti alloys with 72 wt% Al were employed for the realisation of ohmic contacts on 4×1019 cm-3 p-type ion implanted 4H- and 6H-SiC samples. Contact resistivity characterisations by TLM measurements were done at wafer level in the temperature range 28–290°C. Analysis of the TLM measurements took into account current crowding at the metal pads. More than half of the evaluated contact resistivity reached the minimum value detectable by the used TLM devices, that was slightly higher than 1×10-6 Ωcm2. Above this limit value, contact resistivity decreased for increasing temperature and was spread over a few decades. The maximum contact resistivity at 28°C was 2×10-4 Ωcm2, which changed to 5×10-6 Ωcm2 at 290°C. The thermal behaviour of these TLM structures featured thermionic-field emission conduction.

Electrical and interface properties of PdAl/Au metal alloyed ohmic contacts on p-type GaN for high-temperature MEMS devices

2017 ◽  
Vol 28 (22) ◽  
pp. 16903-16909 ◽  
Author(s):  
P. T. Puneetha ◽  
M. Siva Pratap Reddy ◽  
Young-Woong Lee ◽  
Seong-Hoon Jeong ◽  
R. Lokanadham ◽  
...  
Keyword(s):  
High Temperature ◽  
Ohmic Contacts ◽  
Interface Properties ◽  
Mems Devices ◽  
P Type

Formation of p-type layer by KrF excimer laser doping of carbon into GaAs in CH4 gas ambient

1989 ◽  
Vol 49 (6) ◽  
pp. 723-727 ◽  
Author(s):  
K. Sugioka ◽  
K. Toyoda ◽  
K. Tachi ◽  
M. Otsuka
Keyword(s):  
Excimer Laser ◽  
Laser Doping ◽  
Type Layer ◽  
Krf Excimer Laser ◽  
P Type

scholarly journals High Quality Non-Alloyed Pt Ohmic Contacts to P-Type GaN Using Two-Step Surface Treatment

2000 ◽  
Vol 5 (S1) ◽  
pp. 521-527
Author(s):  
Ja-Soon Jang ◽  
Seong-Ju Park ◽  
Tae-Yeon Seong
Keyword(s):  
Surface Treatment ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Transport Mechanisms ◽  
High Quality ◽  
Ammonium Sulfide ◽  
Current Voltage ◽  
Specific Contact ◽  
Thermionic Field Emission ◽  
P Type

Two-step surface-treatment is introduced to obtain low resistance Pt contacts to p-type GaN. The first step is performed after the mesa etching process using buffered oxide etch (BOE) and ammonium sulfide [(NH4)2Sx]. This is followed by the second step using BOE. The Pt contact, which was treated sequentially using ultrasonically boiled BOE (10 min) and boiled (NH4)2Sx (10 min), produces a specific contact resistance of 3.0 (±3.8)×10−5 Ωcm2. However, the contact, that was simply BOE-treated, yields 3.1 (±1.1)×10−2 Ωcm2. This indicates that the two-step surface treatment is promising technique for obtaining high quality ohmic contacts to p-GaN. Investigation of the electronic transport mechanisms using current-voltage-temperature (I-V-T) data indicates that thermionic field emission is dominant in the surface-treated Pt contacts.

Effect of Annealing on the Characteristics of Ti/Al Ohmic Contacts to p-Type 4H-SiC

2017 ◽  
Vol 897 ◽  
pp. 395-398 ◽  
Author(s):  
Yi Dan Tang ◽  
Hua Jun Shen ◽  
Xu Fang Zhang ◽  
Fei Guo ◽  
Yun Bai ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effective Barrier ◽  
Current Voltage ◽  
Key Factor ◽  
Specific Contact ◽  
Different Temperatures ◽  
P Type

Ti/Al contacts deposited on p-type epilayer doped with Al at 2×1019 cm-3 are reported. The current-voltage curves of Ti/Al contacts annealed at different temperatures from 800 to 1000 °C were measured, which provided the specific contact resistances (SCRs) of 6.59×10-5 Ω/cm2 and 7.81×10-5Ω/cm2 after annealing at 900°C for 5min and 950°C for 2min, respectively. The microstructures of Ti/Al contact on P-type 4H–SiC were investigated by X-ray diffraction (XRD). The results of XRD show that the phases of Ti3SiC2 was formed at the metal/SiC interface after annealing, which could be effective to ohmic contacts on P-type 4H-SiC. The quantitative phase analysis were also discussed, which show that the phase composition of Ti3SiC2is key factor for low resistance to P-type 4H–SiC. Moreover, simulations proved that the gradual Ti3SiC2ISL reduces or eliminates the effective barrier height at the metal/Ti3SiC2/p-type and may also contribute to low contact resistivity.

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