摘要:

In focused‐ion‐beam (FIB) applications of micromachining and device transplantation, four kinds of FIB processes, namely FIB sputtering, FIB‐induced etching, redeposition, and FIB‐induced deposition, are well utilized. The first and second processes play the role of ‘‘cutter’’ and the third and last processes play the role of ‘‘attacher’’. In this paper, the characteristics of FIB ‘‘cutter’’ and ‘‘attacher’’ are discussed using previously obtained feasibility experimental data and simple simulations.

ISSN:1071-1023    

DOI:10.1116/1.585661

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

By utilizing the sharpness of a focused ion beam, lateral resolution of SIMS analysis has been improved by one or two orders of magnitude. The authors constructed the submicron SIMS by using a gallium focused ion beam. On the other hand, a focused ion beam is frequently used as a tool for micromachining due to its high current density and sharpness.Insitucombination of micromachining and high spatial resolution analysis brings a new field of microbeam analysis on materials. In the development of thin‐film multilayer devices or large scale integrated circuits, three‐dimensional analysis of local microstructure has a great importance. In order to determine location and composition of a specific subsurface microstructure, a focused ion beam is used as (1) a machining tool to expose a vertical cross section on which the center of the specific microstructure lays, and (2) a primary beam of SIMS element mapping. Through the analysis of a buried fine particle, the submicron SIMS is shown to be a powerful tool for three‐dimensional analysis of a microstructure.

ISSN:1071-1023    

DOI:10.1116/1.585662

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We investigated the halo around the carbon film deposited by a focused ion beam (FIB) for photomask repair. The halo size depends significantly on the operating condition of the liquid metal ion source (LMIS). The LMIS operation with high temperature and/or high emission current produces the large halo around the deposited film. It seems that the halo production is mainly due to the deposition by the broad tail of the FIB. We also measured the energy distributions of the ions emitted from the LMIS. According to our measurement, the tendency of the energy spread agrees qualitatively with the halo size.

ISSN:1071-1023    

DOI:10.1116/1.585663

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The properties of tungsten films and W–GaAs contact characteristics formed by low energy ion beam assisted deposition (IBAD) have been investigated. For the deposition of tungsten films, low energy (0.5–4.0 keV) H2+and Ar+beams were irradiated in W(CO)6ambient. The deposition rate was higher for heavier ion (Ar+) and higher ion energy because of higher energy deposition rate. The deposited films consisted of about 75% of tungsten and 11%–14% of oxygen and carbon, respectively. The resistivity of deposited films was about 600–800 μΩ cm. The damage induced during ion beam irradiation was examined by W–GaAs contact characteristics. The results suggest that it is desirable to use lighter ion and lower ion energy to reduce the damage on the substrate.

ISSN:1071-1023    

DOI:10.1116/1.585664

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The silicon oxide deposition technique with a Si focused ion beam was applied to rewiring from the first aluminum line below a wide power line in a 256k CMOS SRAM. The widths of the power line and the first aluminum line were 130 and 1.5 μm, respectively. First, the layer on the first aluminum line was etched for an area of 4.5×4.5 μm by a Ga focused ion beam. Second, silicon oxide was deposited into the hole using a 60‐keV Si2+focused ion beam with a mixed gas of tetramethoxysilane and oxygen, then, the deposited silicon oxide film was etched for an area of 2×2 μm down to the first aluminum line by the Ga focused ion beam. Last, tungsten was deposited for rewiring from the first aluminum line using the conventional focused ion beam method. The leak current measured between the deposited tungsten and the power line was 1×10−8A at 5 V which is sufficiently small for operation analyses of semiconductor devices.

ISSN:1071-1023    

DOI:10.1116/1.585665

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The etching characteristics of GaAs bombarded with 20 keV Ga+ion beam during impingement of Cl2gas flux have been investigated. At room temperature, an etch yield (the number of substrate atoms removed per ion) with showered ion beam irradiation approaches a saturated value of 101 atoms/ion with the increase in gas flux for different incident ion fluxes of the order of 1014ions/s/cm2. A previously proposed etching model which accounted well for the experimental results for Si/Cl2is in good agreement with the present results. Variation of etch depth computed by this model for focused ion beam raster scanning also agrees with the experimental results. However, as the substrate temperature rises up to 110 °C, the etch yield increases as opposed to the case of Si/Cl2and the saturated etch yield becomes 430 atoms/ion. It seems that formation of several layers of chlorinated compounds might be responsible for the increase in etch yield. Finally, fabrication of multineedle field electron emitter is demonstrated.

ISSN:1071-1023    

DOI:10.1116/1.585666

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We have been investigating the characteristics of the ion beam assisted etching (IBAE) of GaAs performed using a Ga low energy focused ion beam (FIB) and Cl2gas. The etch yield increased monotonously with increasing the Cl2flow rate and showed a tendency to saturate at a high Cl2flow rate. At a flow rate of 7×1018molecules/cm2 s and an ion current density of about 5 mA/cm2, etch yields of 18–52 atoms/ion were obtained for 0.2–15 keV Ga+beams. The IBAE to physical sputter etching ratio was about 14 at 1 keV and above and became larger for lower energy. The etch yield of IBAE varied in proportion to the deposited energy at the surface. Residual chlorine was below the detection limit after IBAE by Auger electron spectroscopy. The radiation damage was estimated by photoluminescence (PL) measurements. After 600 °C annealing, full recovery of PL intensity was observed for IBAE at the energy of 0.2 keV.

ISSN:1071-1023    

DOI:10.1116/1.585667

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Focused ion beam (FIB) induced tungsten deposition is a very promising candidate for the repair of clear x‐ray mask defects. However, it requires careful process control due to the sputtering which accompanies deposition. To improve our understanding of the process and to optimize its parameters in view of high‐throughput mask repair, we developed a model of FIB induced deposition. It is based on a model reported previously, but additionally includes two parameters of outstanding importance for the process: the FIB’s dwell time and its loop time. The model was tested by applying it to the results of deposition experiments in which the influence of various parameters on the growth rate was investigated. Based on that comparison between experiment and theory, we make a prediction on the achievable repair speed as a function of the defect size. In our experiments, we obtained deposition rates of up to 20 nm/s. The x‐ray opacity of the deposited layers is in the order of 80% of the tungsten bulk value.

ISSN:1071-1023    

DOI:10.1116/1.585668

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We have observed focused ion beam (FIB) induced deposition of tungsten on vertical sidewalls. This phenomenon allows high aspect ratio structures such as deep holes to fill with greater efficiency than expected from yields measured when the ion beam is at normal incidence to the surface. However we have also observed indirect deposition on vertical sidewalls which face a clear defect (an area which is missing x‐ray absorber) on an x‐ray mask that had to be repaired by depositing x‐ray absorbing material. Since tungsten is used for both IC microstructuring and x‐ray mask repair, deposition on vertical sidewalls can be exploited for certain repair processes on these structures. However we also propose ways of reducing the effect when deposition distorts facing vertical sidewalls on x‐ray masks.

ISSN:1071-1023    

DOI:10.1116/1.585669

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We have demonstrated the possibility ofinsitutwo‐dimensional electron gas (2DEG) fabrication in GaAs/AlGaAs heterostructures, using focused ion beam implanter and molecular beam epitaxy (FIBI‐MBE) crystal growth system. 2DEGs are formed in a GaAs channel layer which is overgrown on an AlGaAs electron supply layer implanted selectively with Si‐FIBs. Implanted Si atoms are activated by rapid thermal annealing (RTA). We confirmed 2DEG formation by Shubnikov–de Haas oscillation. We clarified the influence of ion implantation damage on the quality of overgrown epilayers and obtained an extremely high 2DEG mobility of 32 000 cm2/V s at 77 K and 48 000 cm2/V s at 20 K. We also discussed possible quantum‐size doping by direct FIB implantation, considering the lateral scattering of incident Si ions in the substrate.

ISSN:1071-1023    

DOI:10.1116/1.585670

出版商:American Vacuum Society    

年代:1991

数据来源: AIP