The slow-positron annihilation technique (SPAT) has been used on silicon samples implanted with BF₂⁺ and F⁺ + B⁺ to study the irradiation defects in the thin surface layer (approximately 700 A). A 7.3-mCi ²²Na source (τ _1/2 = 2.6 years) in front of a single crystal W moderator foil with a thickness of 25 μm was used to produce a slow positron beam. The positron-annihilation characteristics were measured with a solid-state Ge-detector at a number of different incident-positron energies (0.1-2.5 keV) and gave the information about various defects, in particular about vacancy-like defects. BF₂⁺ molecular ion implants were performed at the same atomic flux and fluence as the F⁺ + B⁺ atomic ion double implants. The energy was chosen as 3 keV amu^-1 so that the near surface damage induced by molecular effects could be distinguished from the bulk damage. The calculation of the ds parameter from the SPAT measurements shows the depth profiling of defects in the thin surface layer and approximately 40% more damage created by molecular ion implants. These results are consistent with that from the high resolution Rutherford Backscattering and channelling technique by using a grazing angle detector geometry (scattering angle θ = 97°). It demonstrates that SPAT is a powerful and sensitive technique for measuring the defects distribution in the thin surface layer of a single crystal semiconductor.

Xiaoqin Li;Chenglu Lin;世昌 邹;Heiming Weng;Xuedian Han

Vacuum

1991

Total ionizing dose (TID) effect and single event effect (SEE) from space may cause serious effects on bulk silicon and silicon on insulator (SOI) devices, so designers must pay much attention to these bad effects to achieve better performance. This paper presents different radiation-hardened layout techniques to mitigate TID and SEE effect on bulk silicon and SOI device and their corresponding advantages and disadvantages are studied in detail. Under 0.13 μm bulk silicon and SOI process technology, performance comparisons of two different kinds of DFF circuit are made, of which one kind is only hardened in layout (protection ring for bulk silicon DFF, T-gate for SOI DFF), while the other kind is also hardened in schematic such as DICE structure. The result shows that static power and leakage of SOI DFF is lower than that of bulk silicon DFF, while SOI DFF with T-gate is a little slower than bulk silicon DFF with protection ring, which will provide useful guidance for radiation-hardened circuit and layout design.

Lingjuan Lü;Ruping Liu;Min Lin;Zehua Sang;世昌 邹;Genqing Yang

Journal of Semiconductors

2014-6

Plasma-enhanced chemical vapor deposited Si₃N₄ thin film with a thickness of 140 nm was used as a mask to form shallow junctions by Si ion implantation. The implantation energy ranged from 60 to 120 keV and the doses were 4×10¹⁴ cm^-2 and 1×10¹⁵ cm^-2. Rapid thermal annealing was carried out at temperatures ranging from 850 up to 1050°C for 5 s. The active layers were characterized by HL5900 Stripping Hall System. Junctions as shallow as 30 to 200 nm were formed with electron concentrations of about 10¹⁸ cm^-3. It was found that the electron concentrations at the depth close to the surface were anomalously lowered and the results obtained by TRIM'91 program simulation. By coimplantation of P ions, the activation efficiency of silicon increased greatly. The electron concentration profile configuration fits well the simulated one. An electron concentration as high as about 10¹⁹ cm^-3 was obtained near the surface.

H. L. Shen;H. L. Xu;G. Q. Xia;世昌 邹;Z. Y. Zhou;B. Y. Jiang;X. H. Liu

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

1993-6-3

The hysteresis effect in the output characteristics of partially depleted (PD) silicon-on-insulator (SOI) floating-body MOSFETs with an ultra-thin gate oxide is studied taking account of both gate direct-tunnelling and impact ionization-induced hot-carrier mechanisms. It is proposed that hole tunnelling from valence band (HVB) for floating-body PD SOI n-MOSFETs, electron tunnelling from conduction band (ECB) for floating-body PD SOI p-MOSFETs and impact-ionization-induced hot carriers are the main causes of the hysteresis effect. Meanwhile, body-contact structures of T-gate and H-gate PD SOI MOSFETs are also studied under floating-body configurations. It is found that the influence of the converse poly-gate on the body-contact side on gate direct-tunnelling cannot be neglected in view of floating-body potential variation. Based on the measurement results, the hysteresis can be suppressed using T-gate and H-gate PD SOI MOSFETs with floating-body configurations.

Jianhua Zhou;Albert Pang;世昌 邹

Journal Physics D: Applied Physics

2011-2-23

Some special effects of SOI devices with diamond layout are analyzed in this paper based on the silicon data from 130 nm PD-SOI T-gate MOSFET. LCE and PAMDLE induced current gain dependence on geometry parameters of devices with fixed gate area and fixed smallest channel lengths are presented. BVDS of different diamond devices are studied and discussed and a specified geometry has been found with better BVDS performance. For the special shape of channel region, the hot-carrier effect induced body current is collected in the experiment and the mechanism of body current increasing has been analyzed theoretically.

Xiaonian Liu;Lihua Dai;Pingliang Li;世昌 邹

Microelectronics Journal

2020-5

An expression for the exchange coupling between two magnetized layers embedded in a nonmagnetic metal has been derived analytically within the contact interaction approximation. The coupling generally oscillates with multiple periods which depend on the orientation of the magnetized layers and the specific shape of the metal Fermi surface. The oscillatory periods are related to the extreme and saddle points of the Fermi surface which is given in the periodic zone scheme. The results obtained are quite general and allow us, in principle, to predict the oscillation periods for any metal. The long periods observed in the recent experiments manifest themselves naturally. The bound states that occurred in the model are discussed briefly.

Wang Shaofeng;Zhongcheng Wang;世昌 邹

Physical Review B - Condensed Matter and Materials Physics

1996

A radiation-hardened low-jitter phase-locked loop (PLL) with a low-mismatch charge pump and a robust voltage-controlled oscillator is designed in a 130 nm PD-SOI process. In order to evaluate the overall response to single-event effects, the accumulated phase jitter has been put forward, which can exclude the inherent noise floor and accumulate all the radiation-induced noise. Then the single-event sensitivity of the proposed PLL is comprehensively analyzed by heavy ion and pulsed laser tests.

Zhuojun Chen;Min Lin;Ding Ding;Yunlong Zheng;Zehua Sang;世昌 邹

IEEE Transactions on Nuclear Science

2017-1

An attempt to locate the origin of ion bombardment effect on Ti(C,N,O) film hardness was made. The films were prepared using Ar⁺ ion beam controlled deposition (IBCD) on an Si crystal substrate. Samples from different acceptance angles were exposed to either an alternate sputter-deposition and ion bombardment mode or to a concurrent process. TEM, XTEM, and DCD were used to measure composition and stress parameters. Results showed that there was a decrease in film hardness in all IBCD films subjected to assisting ion bombardment. This was attributed to compactness reduction at lower deposition rates although composition parameters showed no direct correlation.

Youshan Chen;Yilin Sun;Fumin Zhang;Haichuan Mou;Wei Tao;世昌 邹

1993

The amorphous carbon film was prepared through the low-energy ion-beam-assisted-deposition with a single ion source, and the Raman spectroscopy and Auger electron spectroscopy were used to investigate its structure which is proved to be of DLC. It was found that (1) most of the bonds formed in the film are of graphite bonds (sp²) and the film contains less hydrogen, hence the properties of the film are similar to that of graphite i.e. the film has good tribological performance; (2) the friction coefficient, the life-time and the microhardness of the film all increase as the ion energy and the beam current increase. the results show that the DLC film has great potential in the application of magnetic recording system as a wear-resistant protecting film.

Hong Zhu;Xianghuai Liu;Congxin Ren;世昌 邹;Huiwen Liu;Xushou Zhang

Mocaxue Xuebao/Tribology

1995-4

Reactive deposition epitaxial growth of β-FeSi₂ film on Si(111) has been studied by in situ observation of reflective high energy electron diffraction combined with ex situ Auger electron spectroscopy depth profile analysis. The direct phase formed at the top surface after iron coverage has been determined to be mixture Fe₃Si and Fe₅Si₃, FeSi, and β-FeSi₂, respectively, according to the results of different deposit temperature. Diffraction patterns as well as the depth profile for the Fe/Si ratio have been discussed.

Lianwei Wang;Chenglu Lin;Qinwo Shen;Xian Lin;Rushan Ni;世昌 邹

Applied Physics Letters

1995