Arsenic Diffusion and Segregation Behavior at the Interface of Epitaxial CoSi2 Film and Si Substrate

1993 ◽  
Vol 320 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tan ◽  
P. L. Smith ◽  
G. E. Mcguire
Keyword(s):  
Qualitative Agreement ◽  
Film Formation ◽  
Formation Temperature ◽  
Si Substrate ◽  
Free Surfaces ◽  
Si Substrates ◽  
Segregation Behavior ◽  
P Type ◽  
Physical Reasons ◽  
Source Materials

ABSTRACTArsenic diffusion and segregation properties at the interface of the epitaxial CoSi2 and Si substrate have been studied. Samples have been prepared using Co-Ti bimetallic source materials and two types of (001) Si substrates: n+ (doped by As to ∼2}1019 cm−3) and p. For the n+ Si cases, the lower limit of the CoSi2 film formation temperature is increased by ∼200°C to ∼700°C. SIMS results showed As segregation into Si. For epitaxial CoSi2 film formation at 900°C, the As concentration has increased by a factor of ∼2 within a distance of ∼30nm from the interface, while the incorporated As in the film is ∼30-50 times less than that in Si. For p-type Si substrate cases, the epitaxial CoSi2 film was first grown and followed by As+ implantation (into the film) and drive-in processes. It is observed that As was segregated to the CoSi2-Si interface and diffused into Si. This is in qualitative agreement with our results obtained from the n+ substrate experiments and the results of other authors involving the use of polycrystalline CoSi2 films. In the present cases, all implanted As were conserved at a drive in-temperature of 1000°C for up to 100 s. This is in contrast to the polycrystalline CoSi2 film results which involve a substantial As loss to the film free surfaces. The physical reasons of this difference have been discussed.

Formation Mechanism of Epitaxial CoSi2 Films on (001) Si Using Ti-Co Bimetallic Layer Source Materials

1992 ◽  
Vol 280 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tana ◽  
P. L. Smith ◽  
G. E. Mcguire
Keyword(s):  
Film Formation ◽  
Substrate Surface ◽  
Native Oxide ◽  
Formation Processes ◽  
Mechanism Of Formation ◽  
Si Substrate ◽  
Barrier Material ◽  
Si Substrates ◽  
Bimetallic Layer ◽  
Source Materials

ABSTRACTThe mechanism of formation of epitaxial CoSi2 film on (001) Si substrate, produced using sequentially deposited Ti-Co bimetallic layer source materials for which Ti was deposited onto the Si substrates first, has been studied by observing the Co silicide formation processes and structures in samples prepared by isochronal annealing and by isothermal annealing. The results demonstrated that, in leading to epitaxial CoSi2 film formation, Ti has played two roles. It has served as a barrier material to Co atoms and thus preventing Co2Si from forming. More importantly, it has allowed nucleation and growth of epitaxial-CoSi2 to dominate the Co silicide film formation process, apparently because it has served as a cleanser to remove native oxide from the Si substrate surface.

CoSi and CoSi2 Phase Formation on Bulk and Soi Si Substrates

1993 ◽  
Vol 320 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tan ◽  
P. L. Smith ◽  
G. E. Mcguire
Keyword(s):  
Free Energy ◽  
Energy Release ◽  
Gibbs Free Energy ◽  
High Temperatures ◽  
Phase Formation ◽  
Energy Reduction ◽  
Formation Temperature ◽  
Si Substrates ◽  
Two Phases ◽  
Source Materials

ABSTRACTWe have studied the CoSi and CoSi2 phase formation sequence in (001) bulk and SOI Si wafers, using Co/Ti bimetallic layers as source materials which are suitable for growing epitaxial CoSi2 films on (001) Si. In bulk Si, co-formation of polycrystalline CoSi and epitaxial CoSi2 phases at T>500°C have been observed. These phases form respectively at the metal and Si sides of the film. For very long times and/or at high temperatures, only epitaxial CoSi2 is observed, e.g., for samples annealed at 560°C for 30 min or at 900°C for 10 s. When using (001) SOI Si with inexhaustible Co supply, only polycrystalline CoSi has been formed for a 900°C 10 s annealing, which is in contrast to the bulk Si results. This phenomenon is understood on the basis of Gibbs free energy reduction in forming the two phases. In the CoSi2 formation temperature range, Gibbs free energy release in forming CoSi2 is only ∼10% more than that of forming CoSi. Consequently, after all Si atoms have been consumed, the formation of CoSi becomes energetically more favorable, since the free energy reduction due to formation of 2x mole of CoSi is much larger than that due to formation of lx mole of CoSi2, where x is the SOI Si mole number.

GaAs/AlGaAs Diode Lasers on Monolithic GaAs/Si Substrates

1986 ◽  
Vol 67 ◽  
Author(s):  
T. H. Windhorn ◽  
G. W. Turner ◽  
G. M. Metze
Keyword(s):  
Active Region ◽  
Diode Lasers ◽  
Si Substrate ◽  
Mole Percent ◽  
Double Heterostructure ◽  
Graded Index ◽  
Si Substrates ◽  
Stripe Width ◽  
Power Outputs ◽  
P Type

ABSTRACTOne approach to the development of optical interconnects between Si systems utilizes diode lasers fabricated in III-V epitaxial layers grown on Si wafers. We have fabricated double-heterostructure lasers in GaAs/AlGaAs layers grown on a Ge-coated Si substrate, and both asymmetric largeoptical- cavity (LOC) lasers and graded-index, separate-confinement heterostructure (GRIN-SCH) lasers in such layers grown directly on a Si substrate. The GaAs/AlGaAs layers were grown by molecular beam epitaxy on (100) p-Si substrates. Si and Be were used as the n- and p-type dopants, respectively. Oxide-defined stripe-geometry devices, 300 μm long, were fabricated using standard AuSn and CrAu metallizations for the n- and ptype contacts, respectively. The laser facets were formed by ion-beamassisted etching. The double-heterostructure devices (8 μm stripe width), in which the active region contained about 10 mole percent AlAs, were evaluated using pulsed bias at 77 K. They produced power outputs up to 3.3 mW per facet and exhibited thresholds as low as 170 mA. The LOC devices (4 μm stripe width), which had a GaAs active region, were characterized using pulsed bias at 300 K. These devices produced power outputs up to 27 mW per facet. The lowest threshold was 775 mA. The GRIN-SCH devices (4 μm stripe width), which incorporated a 70 Å GaAs quantum well active layer, were also characterized using pulsed bias at 300 K. These devices were not operated at power outputs above −5 mW. Their lowest threshold was 220 mA.

scholarly journals Impact of Silicon Substrate with Low Resistivity on Vertical Leakage Current in AlGaN/GaN HEMTs

2019 ◽  
Vol 9 (11) ◽  
pp. 2373 ◽  
Author(s):  
Chunyan Song ◽  
Xuelin Yang ◽  
Panfeng Ji ◽  
Jun Tang ◽  
Shan Wu ◽  
...  
Keyword(s):  
Leakage Current ◽  
Impact Ionization ◽  
Electron Injection ◽  
Depletion Region ◽  
High Electron ◽  
Si Substrate ◽  
Low Resistivity ◽  
Si Substrates ◽  
Vertical Leakage ◽  
P Type

The role of low-resistivity substrate on vertical leakage current (VLC) of AlGaN/GaN-on-Si epitaxial layers has been investigated. AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on both p-type and n-type Si substrates with low resistivity are applied to analyze the vertical leakage mechanisms. The activation energy (Ea) for p-type case is higher than that for n-type at 0–600 V obtained by temperature-dependent current-voltage measurements. An additional depletion region in the region of 0–400 V forms at the AlN/p-Si interface but not for AlN/n-Si. That depletion region leads to a decrease of electron injection and hence effectively reduces the VLC. While in the region of 400–600 V, the electron injection from p-Si substrate increases quickly compared to n-Si substrate, due to the occurrence of impact ionization in the p-Si substrate depletion region. The comparative results indicate that the doping type of low-resistivity substrate plays a key role for VLC.

Construction, characterization, and growth mechanism of high-density jellyfish-like GaN/SiOxNy nanomaterials on p-Si substrate by Au-assisted chemical vapor deposition approach

CrystEngComm ◽  
2019 ◽  
Vol 21 (26) ◽  
pp. 3966-3973 ◽  
Author(s):  
Pengkun Li ◽  
Kang Li ◽  
Shujing Sun ◽  
Chenlong Chen ◽  
B. G. Wang
Keyword(s):  
Chemical Vapor Deposition ◽  
Growth Mechanism ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Density ◽  
Si Substrate ◽  
Si Substrates ◽  
P Type

High-density GaN/SiOxNy jellyfish-like nanomaterials are synthesized on Au-coated p-type Si substrates by a chemical vapor deposition approach.

Phase Transformation of Co Silicidation in the Co/Ti- and Ti/Co-Si(100) Systems

1993 ◽  
Vol 311 ◽  
Author(s):  
Feng Hong ◽  
Bijoy K. Patnaik ◽  
Bingzong Li ◽  
Ping Liu ◽  
Zen Sun ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Transformation Temperature ◽  
Interfacial Layer ◽  
Vacuum Furnace ◽  
Phase Identification ◽  
Formation Temperature ◽  
Silicide Formation ◽  
Si Substrate ◽  
Si Substrates ◽  
Selective Diffusion

ABSTRACTCo silicide formed via selective diffusion of Co through a Ti interfacial layer has been reported by several groups. In this report, phase identification of the silicide has been further studied for both Co/Ti and Ti/Co multi- and bilayers deposited on p(100)-Si substrates. The samples were either vacuum furnace or RTA annealed from 550°C to 900°C. The Co silicide formation sequence in the Co/Ti-Si systems follows CoSi2→Co2Si→CoSi→CoSi2 with the formation temperature increasing for each phase. The Co/Ti bilayer CoSi to CoSi2 transformation temperature was lower than that for the six layer Co/Ti system. For the multilayer sample with Co as the first layer in contact with the Si substrate, CoSi2 formed at 550°C and then CoSi was observed at higher temperatures due to the effect of Co supply on disilicide phase instability. Epitaxial CoSi2 growth occured at higher temperatures after the removal of the unreacted upper layers. A 15 μΩ-cm film resistivity was obtained from 50 nm epitaxial CoSi2.

scholarly journals Surface Texturing of Si with Periodically Arrayed Oblique Nanopillars to Achieve Antireflection

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 380
Author(s):  
Jun-Hyun Kim ◽  
Sanghyun You ◽  
Chang-Koo Kim
Keyword(s):  
Aspect Ratio ◽  
Plasma Etching ◽  
Surface Texturing ◽  
Light Reflection ◽  
Si Substrate ◽  
Weighted Mean ◽  
Optical Reflectance ◽  
Si Substrates ◽  
Aspect Ratios ◽  
Shadowing Effect

Si surfaces were texturized with periodically arrayed oblique nanopillars using slanted plasma etching, and their optical reflectance was measured. The weighted mean reflectance (Rw) of the nanopillar-arrayed Si substrate decreased monotonically with increasing angles of the nanopillars. This may have resulted from the increase in the aspect ratio of the trenches between the nanopillars at oblique angles due to the shadowing effect. When the aspect ratios of the trenches between the nanopillars at 0° (vertical) and 40° (oblique) were equal, the Rw of the Si substrates arrayed with nanopillars at 40° was lower than that at 0°. This study suggests that surface texturing of Si with oblique nanopillars reduces light reflection compared to using a conventional array of vertical nanopillars.

scholarly journals Formation and Evaluation of Silicon Substrate with Highly-Doped Porous Si Layers Formed by Metal-Assisted Chemical Etching

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yijie Li ◽  
Nguyen Van Toan ◽  
Zhuqing Wang ◽  
Khairul Fadzli Bin Samat ◽  
Takahito Ono
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Contact Resistance ◽  
Power Factor ◽  
Chemical Etching ◽  
Porous Si ◽  
Si Substrate ◽  
Si Substrates ◽  
Output Performance ◽  
Metal Assisted Chemical Etching

AbstractPorous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact between porous Si and metal is one reason for the reduction of electrical conductivity. In this paper, p- and n-type porous Si were formed on Si substrate by metal-assisted chemical etching. To decrease contact resistance, p- and n-type spin on dopants are employed to dope an impurity element into p- and n-type porous Si surface, respectively. Compared to the Si substrate with undoped porous samples, ohmic contact can be obtained, and the electrical conductivity of doped p- and n-type porous Si can be improved to 1160 and 1390 S/m, respectively. Compared with the Si substrate, the special contact resistances for the doped p- and n-type porous Si layer decreases to 1.35 and 1.16 mΩ/cm2, respectively, by increasing the carrier concentration. However, the increase of the carrier concentration induces the decline of the Seebeck coefficient for p- and n-type Si substrates with doped porous Si samples to 491 and 480 μV/K, respectively. Power factor is related to the Seebeck coefficient and electrical conductivity of thermoelectric material, which is one vital factor that evaluates its output performance. Therefore, even though the Seebeck coefficient values of Si substrates with doped porous Si samples decrease, the doped porous Si layer can improve the power factor compared to undoped samples due to the enhancement of electrical conductivity, which facilitates its development for thermoelectric application.

Coevaporation Effect of Te on P-Type CdTe:Cu Film Formation

1990 ◽  
Vol 29 (Part 2, No. 8) ◽  
pp. L1376-L1378 ◽  
Author(s):  
Mikihiko Nishitani ◽  
Kazue Hisamoto ◽  
Mitsusuke Ikeda ◽  
Takashi Hirao
Keyword(s):  
Film Formation ◽  
P Type

Heteroepitaxial Growth of 3C-SiC on Si (111) Substrate Using AlN as a Buffer Layer

2008 ◽  
Vol 600-603 ◽  
pp. 251-254 ◽  
Author(s):  
Yong Mei Zhao ◽  
Guo Sheng Sun ◽  
Xing Fang Liu ◽  
Jia Ye Li ◽  
Wan Shun Zhao ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Chemical Vapor ◽  
Heteroepitaxial Growth ◽  
Si Substrate ◽  
Si Substrates ◽  
Good Crystallinity ◽  
Aln Film ◽  
Pressure Chemical ◽  
Aln Buffer ◽  
Sic Film

Using AlN as a buffer layer, 3C-SiC film has been grown on Si substrate by low pressure chemical vapor deposition (LPCVD). Firstly growth of AlN thin films on Si substrates under varied V/III ratios at 1100oC was investigated and the (002) preferred orientational growth with good crystallinity was obtained at the V/III ratio of 10000. Annealing at 1300oC indicated the surface morphology and crystallinity stability of AlN film. Secondly the 3C-SiC film was grown on Si substrate with AlN buffer layer. Compared to that without AlN buffer layer, the crystal quality of the 3C-SiC film was improved on the AlN/Si substrate, characterized by X-ray diffraction (XRD) and Raman measurements.

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