The BF₂⁺ beam can be contaminated by BF⁺, F⁺ and B⁺ beams with different energies due to the collisions between BF₂⁺ and the remaining gas molecules in the system. It is unfavourable for shallow junction formation because the junction depth would be increased remarkably as shown by SIMS results. Three methods of removing or decreasing the contamination beams are presented.

Jinhua Li;世昌 邹

Pan Tao Ti Hsueh Pao/Chinese Journal of Semiconductors

1990-4

In this paper, we report on the As redistribution properties in β-FeSi₂ prepared by reactive deposition epitaxy. Unlike the case of solid phase epitaxy, no snow plough effect has been found. Arsenic atoms become resident in the surface silicide layer, indicating that the diffusion process during the reactive deposition is different from the case of solid phase epitaxy. Further annealing drive the arsenic atoms out of the film.

Lianwei Wang;Chenglu Lin;Xiangdong Chen;世昌 邹;Zuyao Zhou;Xianghuai Liu

1996

The chemical composition and structure of silicon on insulator (SOI) formed by the combination of O⁺ (200 keV, 1.8*10¹⁸ cm^-2) and N⁺ (180 keV, 4*10¹⁷ cm^-2) implanted into silicon has been investigated by Auger electron, IR absorption and reflection spectroscopic measurements. After annealing at 1200 degrees C for 2 h, the in-depth composition profiles of the SOI structure show that the nitrogen segregates to the wings of the buried silicon oxide layer where it forms an oxynitride. The characteristic Auger spectrum for the buried oxide layer identified a chemical state of silicon whose major transition at 85 eV is different from that of bulk silicon or silicon in SiO₂ and the ratio of the amplitude of the Si peak at 85 eV to the Si peak at 76 eV remains unchanged in the buried oxide layer. Infrared (IR) absorption and reflection spectra in the wavenumber range 800-5000 cm^-1 were measured for the SOI structure. Interference fringes were observed in the IR spectra. By detailed theoretical analysis and computer simulation of the IR reflection interference spectra, refractive index profiles of SOI structure were obtained.

Yuehui Yu;Chenglu Lin;世昌 邹;P. L.F. Hemment

Journal Physics D: Applied Physics

1990-4

Ion beam synthesis is now being successfully employed to form high quality silicon-on-insulator (SOI) materials for applications to small geometry and radiation resistant LSI devices. However, the rapid development of SOI technology has been hindered by the limited supply of substrate due to its very long implantation times using presently available implanters. This paper reports a new and effective technology for forming cheap thin films SIMNI (Separation by IMplanted NItrogen) material. N-type 〈100〉 Si wafers were implanted with 95 keV, (0.1-1) × 10¹⁸ cm^-2 N₂⁺ and N⁺ by using an ion implanter without mass analysis. After implantation the samples were annealed at 1200°C for 2 h and underwent vapor phase epitaxial growth. Some of the physical and electrical properties of the thin film SIMNI materials were studied by Rutherford backscattering and channeling, cross-sectional transmission electron microscopy, infrared absorption and reflection, spreading resistance measurements. All the results showed that thicknesses of the top silicon layers with minimum channeling yield of 5% are 0.3-1.0 μm and the thicknesses of buried Si₃N₄ layer are 170-200 nm. The Si-Si₃N₄ interfaces are extremely abrupt. In order to obtain good thin film SIMNI materials, the ion implantation dose is an important parameter, which has great influence upon the quality of the top silicon layer.

Chenglu Lin;世昌 邹;Jinghua Li

Vacuum

1991

The direct growth of GaAs by molecular-beam epitaxy (MBE) on silicon-on-insulator (SOI) structure is presented. Rutherford backscattering and channeling (RBS/C), transmission electron microscope (TEM), and infrared (IR) reflection measurements have been employed to characterize the GaAs thin films. RBS/C results show that there is considerable lattice disorder at the GaAs-Si interface, but the crystal quality of the GaAs thin films improves remarkably toward GaAs surface for thicker films where the minimum channeling yield drops to 10% IR reflection spectra in the wavenumber range 1500 - 5000 cm^-1 were measured for GaAs thin films on SOI. Interference fringes observed in IR reflection spectra also prove that the crystalline GaAs thin films have been deposited on SOI substrates. By computer simulation of the IR reflection interference spectra refractive index profiles of the GaAs/SOI structures were obtained.

Wen H. Zhu;Cheng L. Lin;Yue H. Yu;Aizhen Li;世昌 邹;Peter L. Hemment

1991

Optical transition of properties of β-FeSi₂ film have been investigated by optical transmittance absorption measurement, spectroscopic ellipsometry and reflectivity. Optical transmittance absorption measurement ranging from 0.5 to 1.1 eV revealed the direct transition at E₀=0.84 eV, while absorption curve obtained from the spectroscopic measurement in the range of 1.5-4.5 eV implied additional transition at E'=1.05 eV, it is suggested that such additional transition originates from spin-orbit splitting at Γ (center of Brillouin's zone). Reflectivity goes to the maximum value near E_g, indicating that the joint density of states in the transition at E_g is very high. Another peak which is related with the transition at E' was also observed in the reflectivity spectra.

Lianwei Wang;Linhong Qin;Yuxiang Zheng;Wenzhong Shen;Xiangdong Chen;Xian Lin;Chenglu Lin;世昌 邹

Applied Physics Letters

1994

Damaging effect of diatomic phosphorus ions implanted into silicon was compared with that of atomic ions in the range between 25 and 300 keV/atom. Dose was around 1014 ions/cm ². Target temperature varied between 77 and 533 K. Below and at 300 K the “damage enhancement factor” defined as ratio of damage produced by equivalent molecular and atomic ion implantation varied from 1 to 1.6 depending on incident energy. At elevated implantation temperature this factor increased by almost an order of magnitude. In interpretation of experimental results, fluctuations in damage structure inside the volume of collision cascades was proposed. Conclusions are believed to be relevant for other molecular implantation, e.g. for the BF₂₊.

G. Q. Yang;L. C. Lu;世昌 邹;N. Q. Khanh;M. Fried;E. Kotai;V. Schiller;J. Gyulai

Radiation Effects and Defects in Solids

1990-11

SIMNI material was formed by N⁺ implantation into crystalline silicon wafers at 170 keV with a dose of 1.8 × 10¹⁸ cm^-2 and annealing at 1200° C for 2 h. The top silicon of these SIMNI wafers was amorphized at different depths by Si⁺ implantation at three conditions: (1) 25 keV, 5 × 10¹⁵ cm^-2; (2) 140 keV, 5 × 10¹⁵ cm^-2; (3) 25 keV, 5 × 10¹⁵ cm^-2 + 80 keV, 5 × 10¹⁵ cm^-2 + 140 keV, 5 × 10¹⁵ cm^-2. Then the three groups of SIMNI wafers and another group with no implantation by Si⁺ were implanted by B⁺ at 25 keV with a dose of 1 × 10¹⁵ cm^-2, and annealed at a series of temperatures for 30 min. Glancing RBS/C measurement shows that an epitaxial regrowth toward the surface or the inner part of the top silicon exists for the samples in group (1) and (2), respectively, with increasing annealing temperature. No epitaxial regrowth exists for the samples in group (3). Raman measurement shows that a phase transformation from amorphized silicon to polysilicon exists for the top silicon of samples in group (3) when the annealing temperature is increased from 500° C to 600° C. SRP measurement shows that Si⁺ + B⁺ dual implantations are able to increase the activation rate of boron in the top silicon of SIMNI material.

Shunkai Zhang;Chenglu Lin;Zuyao Zhou;世昌 邹

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

1991-4-2

Layered structures such as silicon on insulator (SOI), and Si₃N₄ on silicon have been synthesized by different ion beam techniques and investigated by infrared (IR) reflection and absorption. Auger electron spectroscopy (AES) and cross-sectional transmission electron microscopy (XTEM). Buried SiO₂, Si₃N₄ and SiO_xN_y layers in silicon have been formed by oxygen (200 keV 1.8 × 10¹⁸ O⁺/cm²) or nitrogen (190 keV, 1.8 × 10¹⁸ N⁺/cm²) implantation and by dual implantation of oxygen (200 keV, 1.8 × 10¹⁸ O⁺/cm²) and nitrogen (180 keV, 4 × 10¹⁷ N⁺/cm²) into silicon and annealing at different temperatures. Silicon nitride films with a stoichiometric ratio of Si₃N₄ have been synthesized by ion beam enhanced deposition (IBED). Infrared reflection spectra in the wavenumber range 1700-5000 cm^-1 were measured for the SOI structures and Si₃N₄ films on silicon. Refractive index profiles of the SOI structures and Si₃N₄ films on silicon were obtained by computer simulation of the IR reflection interference spectra. In-depth composition profiles of the Si₃N₄ film on silicon have been correlated with its refractive index profiles using the Lorentz-Lorenz equation. The results of IR analysis are in agreement with AES and XTEM results.

Yuehui Yu;Chenglu Lin;Xianghuai Liu;世昌 邹;P. L.F. Hemment

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

1991-4-2

In this paper, a study on the dry thermal oxidation of a graded SiGe layer is proposed. By oxidation of a graded SiGe layer, the effect of Ge pileup was reduced and dependence of the oxidation ambient was analyzed. During oxidation at pure oxide ambient, pure compositions of silicon dioxide are formed without dislocation, and it was clearly proved by the TEM, EDS, SE, and AFM results. Whereas, after oxidation under atmospheric pressure with 2l/min mix gas flow of Ar50%+O₂50%, composition of SiGeO₂ was found at the top layer. This result can propose an oxidation method optimization of SiGe/Si heterostructures.

Z. J. Chen;F. Zhang;X. Wang;世昌 邹

2004