DIRECT SUPPORT BY SPOT WELDING AND CHEMICAL ETCHING OF COMPOUND SEMICONDUCTOR WHISKER

T. Inoue; M. Nakada

doi:10.1051/jphyscol:1987697

A Compound Semiconductor Process Simulator and its Application to Mask Dependent Undercut Etching

VLSI Design ◽

10.1155/1998/65787 ◽

1998 ◽

Vol 6 (1-4) ◽

pp. 393-397

Author(s):

Masami Kumagai ◽

Kiyoyuki Yokoyama ◽

Satoshi Tazawa

Keyword(s):

Chemical Etching ◽

Compound Semiconductors ◽

Compound Semiconductor ◽

Mask Material ◽

Atomic Species ◽

Deposition Processes ◽

Different Response ◽

Process Simulator ◽

Good Agreement ◽

Semiconductor Process

This paper describes a process simulator that is designed to describe the etching and deposition processes used in constructing compound semiconductors, which have at least two different atomic species. This nature dictates a very different response to compound semiconductor process from the silicon process. One of the most remarkable processes in compound semiconductors is the reverse-mesa formation. This simulator successfully represents the mesa and the reverse mesa profiles that are often observed after chemical etching. The mask material dependence of the undercut etching can also be simulated with a good agreement between the experimental and the simulated shapes.

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The observation of defects on (100) CdTe surfaces by chemical etching

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131759 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1424-1425

Author(s):

M.E. Lee

Keyword(s):

Single Crystal ◽

Grain Boundaries ◽

Single Crystals ◽

Chemical Etching ◽

Crystalline Perfection ◽

Crystalline Defects ◽

High Incidence ◽

Crystallographic Defects ◽

Cdznte Substrates ◽

Device Technology

The crystalline perfection of bulk CdTe substrates plays an important role in their use in infrared device technology. The application of chemical etchants to determine crystal polarity or the density and distribution of crystallographic defects in (100) CdTe is not well understood. The lack of data on (100) CdTe surfaces is a result of the apparent difficulty in growing (100) CdTe single crystal substrates which is caused by a high incidence of twinning. Many etchants have been reported to predict polarity on one or both (111) CdTe planes but are considered to be unsuitable as defect etchants. An etchant reported recently has been considered to be a true defect etchant for CdTe, MCT and CdZnTe substrates. This etchant has been reported to reveal crystalline defects such as dislocations, grain boundaries and inclusions in (110) and (111) CdTe. In this study the effect of this new etchant on (100) CdTe surfaces is investigated.The single crystals used in this study were (100) CdTe as-cut slices (1mm thickness) from Bridgman-grown ingots.

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Microstructure of resistance spot welding of maraging steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177635 ◽

1990 ◽

Vol 48 (4) ◽

pp. 900-901

Author(s):

I. Neuman ◽

S.F. Dirnfeld ◽

I. Minkoff

Keyword(s):

Maraging Steel ◽

Spot Welding ◽

Lath Martensite ◽

Base Material ◽

Aging Treatment ◽

High Strength ◽

Maraging Steels ◽

Heat Treated ◽

Current Cycle ◽

Welding Processes

Experimental work on the spot welding of Maraging Steels revealed a surprisingly low level of strength - both in the as welded and in aged conditions. This appeared unusual since in the welding of these materials by other welding processes (TIG,MIG) the strength level is almost that of the base material. The maraging steel C250 investigated had the composition: 18wt%Ni, 8wt%Co, 5wt%Mo and additions of Al and Ti. It has a nominal tensile strength of 250 KSI. The heat treated structure of maraging steel is lath martensite the final high strength is reached by aging treatment at 485°C for 3-4 hours. During the aging process precipitation takes place of Ni3Mo and Ni3Ti and an ordered solid solution containing Co is formed.Three types of spot welding cycles were investigated: multi-pulse current cycle, bi-pulse cycle and single pulsle cycle. TIG welded samples were also tested for comparison.The microstructure investigations were carried out by SEM and EDS as well as by fractography. For multicycle spot welded maraging C250 (without aging), the dendrites start from the fusion line towards the nugget centre with an epitaxial growth region of various widths, as seen in Figure 1.

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