摘要:

Scanning tunneling microscopy (STM) and transmission electron microscopy (TEM) were used to quantify and characterize CoSi2surface roughness and CoSi2/Si interface roughness. Roughness at the CoSi2/Si interface has been reported to be on the order of 20 nm, enough for concern in shallow junction formation in submicron complementary metal–oxide semiconductor devices. Interface roughness is tied to surface roughness by thermal grooving kinetics and by thermodynamics. Hence, a correlation should be seen between roughness at the interface and the surface, yielding information regarding grooving kinetics. This study focused on the processing time dependence of surface and interface roughness. This roughness was quantified using the average roughness measurement technique. The roughness values obtained by TEM were compared to those obtained by STM. Both were fitted to thermal grooving kinetics equations.

ISSN:1071-1023    

DOI:10.1116/1.585863

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

In a recent article we pointed out the importance of final state effects in the context of Schottky‐barrier measurements by core‐level photoemission. Using a wave vector‐dependent image‐screening model, we concluded that final state effects give a substantial contribution to the estimated Schottky‐barrier height. In the present comment the list of supporting evidence is extended by new experimental work emphasizing the difference in final state screening at metal and semiconductor surfaces. We find that the measured differences are well reproduced by the screening model with similar parameters as used in our earlier discussion of Schottky barriers.

ISSN:1071-1023    

DOI:10.1116/1.585864

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

High‐quality copper films were deposited from the β‐diketonate precursor copper(II) (hexafluoroacetylacetonato), Cu(hfa2), using a remote plasma chemical vapor deposition (RPCVD) process which allows the delivery to the reaction zone of the reactive hydrogen species (mostly atomic and ionic hydrogen) needed for precursor reduction while avoiding plasma‐induced substrate damage. The RPCVD process was employed to grow copper films at temperatures in the range 150–250 °C at a reactor pressure and plasma power of, respectively, 0.5–2 Torr and 75–100 W (power density of 1.5–2.2 W/cm2), with an average copper growth rate of 50–75 Å/min. Films thus grown were analyzed by x‐ray diffraction, Rutherford backscattering, x‐ray photoelectron spectroscopy, four‐point resistivity probe, and scanning electron microscopy. The results of these studies showed that the films were pure (impurity levels were below the detection limits of the techniques used), uniform, continuous, and had resistivity values under 2.0 μΩ cm.

ISSN:1071-1023    

DOI:10.1116/1.585865

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.585866

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.585867

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

High‐quality semiconductor material is essential to the production of high performance, affordable semiconductor components. With infrared (IR) components, the maturity and quality of the material has an increased significance, affecting not only component characteristics, but also system performance and cost. The criteria for selection of the focal plane material involves consideration of the system cooling requirements, spectral band, nonuniformity correction, and even system reliability. Each of these system parameters has a direct relationship to the IR material. The system requirements place demands on the quality and cost of the starting material and help to define the appropriate material growth technique, wafer size, the requirements for on‐chip signal processing, and relevant material figures‐of‐merit. A concurrent engineering approach to IR material development is necessary, taking into account both the material limitations and the demands of the infrared imaging system for the proposed application. In addition to the material performance figures‐of‐merit, the impact of the material on device fabrication and system cost must be taken into account. Ideally, a quantitative assessment of the effect of IR material characteristics on detector module cost and on system complexity should guide this process. Mercury cadmium telluride (MCT) has been the dominant IR material for a broad range of system applications. However, the cost and availability of the MCT are major considerations in the production of affordable IR local plane arrays. This article discusses these general issues relative to the state‐of‐the‐art of this IR material, and provides generic guidelines for the selection of material for IR imaging applications.

ISSN:1071-1023    

DOI:10.1116/1.585868

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

Technological limits, not fundamental issues, are all that keep HgCdTe from completely dominating almost all infrared (IR) applications. The technological limits result from our incomplete understanding of HgCdTe materials science. This article’s snapshot view, from the unique perspective of the major United States HgCdTe IR detector array companies, suggests directions that HgCdTe detector technology should take as we approach the next century. We argue that the Government, industrial users, and industrial producers of HgCdTe must support continuing scientific investigation of this material to parallel the manufacturing of second generation HgCdTe‐based systems. Without this manufacturing science base, systems will develop too slowly, cost too much, and fail too often. To assist developing this critically important technology, the article highlights some of the more vexing and as yet unsolved HgCdTe materials science and engineering problems that we see as being important.

ISSN:1071-1023    

DOI:10.1116/1.585869

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

(111) CdTe has been grown on both GaAs/Si and Si by hot wall epitaxy. X‐ray diffraction, photoluminescence, and defect etching indicate that these layers are of high crystalline quality. For CdTe grown on GaAs/Si, full width at half‐maximum of x‐ray rocking curves as low as 59 arcsec have been obtained whereas for CdTe grown on Si, x‐ray linewidths as narrow as 315 arcsec have been obtained. HgCdTe grown on (111)B CdTe/GaAs/Si by metalorganic chemical vapor deposition is very smooth and devoid of the many defects that plague other orientations.

ISSN:1071-1023    

DOI:10.1116/1.585870

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

In this article, we report on the low temperature growth of HgTe, CdTe, and HgCdTe by flow modulation epitaxy (FME). Dimethylmercury, dimethylcadmium, and methylallyltelluride were used as the precursors in this ‘‘layer‐by‐layer’’ growth approach. Growth of CdTe at one monolayer per cycle was obtained at temperatures above 250 °C. The growth rate was invariant with temperature and reactant pressures. HgTe growth was carried out by FME at 140 °C at atmospheric pressure by precracking the Hg and Te alkyls at 350 °C. HgCdTe layers were grown by interdiffusing sequential layers of CdTe and HgTe.

ISSN:1071-1023    

DOI:10.1116/1.585871

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

Hg1−xCdxTe growth was studied, evaluating the uniformity in terms of the composition, thickness, and surface morphology. Growth was done on a 3 in. GaAs substrate in a vertical reactor using metalorganic chemical vapor deposition featuring a rotating susceptor with multiple nozzles. In a simulation based on the results of our experiment, we found that eight nozzles are needed to grow an epilayer having a compositional variation (Δx) within 0.002. Hg1−xCdxTe was grown using eight nozzles after a CdTe (111)B buffer layer was grown on a 3 in. GaAs (100) wafer. The maximum variation inx(Δx) was 0.010, and the mean value (x̄) was 0.264 over the full surface of the 3 in. diam wafer. The thickness variation (Δd) was 0.7 μm, and the mean value (d̄) 5.7 μm. An evaluation of the surface morphology showed a specular surface with small triangular pits. The etch pit density was 2.6–7.4×106cm−2.

ISSN:1071-1023    

DOI:10.1116/1.585872

出版商:American Vacuum Society    

年代:1992

数据来源: AIP