Characterization of Si pn junctions fabricated by direct wafer bonding in ultra-high vacuum

ABSTRACTWe report on the characterization of germanium quantum dots grown on silicon (001) substrates by ultra-high vacuum chemical vapor deposition (UHV/CVD). In many applications small and uniform quantum dots are required which must be overgrown by a silicon epitaxial layer. We report here on the effect of carbon predeposition from methylsilane on the dot size and uniformity. In addition, we use reciprocal space mapping to evaluate the qualityof epitaxial layers which overgrow the quantum dots. The results show some differences from previous reports on MBE-grown dots.

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Preparation and spectroscopic characterization of a thin polymer film in ultra high vacuum: 2,5‐distyrylpyrazine

The Journal of Chemical Physics ◽

10.1063/1.459793 ◽

1991 ◽

Vol 94 (4) ◽

pp. 3235-3241 ◽

Cited By ~ 4

Author(s):

M. Abraham ◽

J. Dütting ◽

M. Schreck ◽

R. Lege ◽

S. Reich ◽

...

Keyword(s):

Polymer Film ◽

High Vacuum ◽

Spectroscopic Characterization ◽

Ultra High Vacuum ◽

Thin Polymer Film ◽

Thin Polymer

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Gas-Tight Oxides - Reality or Just a Hope

Materials Science Forum ◽

10.4028/www.scientific.net/msf.522-523.93 ◽

2006 ◽

Vol 522-523 ◽

pp. 93-102 ◽

Cited By ~ 10

Author(s):

C. Anghel ◽

Gunnar Hultquist ◽

Qian Dong ◽

J. Rundgren ◽

Isao Saeki ◽

...

Keyword(s):

Mathematical Model ◽

High Vacuum ◽

Ultra High Vacuum ◽

Gas Content ◽

Molar Ratio ◽

Protection Measure ◽

Straightforward Method ◽

Gas Tight ◽

The Mathematical Model

A better understanding of the transport properties of gases in oxides is certainly very important in many applications. In the case of metals, a general protection measure against corrosion implies formation of a dense metal oxide scale. The scale should act as a barrier against gas transport and consequently it needs to be gas-tight. This is often assumed but rarely, if ever, confirmed. Hence there is a need for characterization of micro- and/or meso- pores formed especially during the early oxidation stage of metallic materials. This paper presents a novel and relatively straightforward method for characterization of gas release from an oxide previously equilibrated in a controlled atmosphere. The geometry of the sample is approximated to be a plate. The plate can be self-supporting or constitute a scale on a substrate. A mathematical model for calculation of diffusivity and gas content is given for this geometry. A desorption experiment, involving a mass spectrometer placed in ultra high vacuum, can be used to determine diffusivity and amount of gas released with aid of the mathematical model. The method is validated in measurements of diffusivity and solubility of He in quartz and applied in characterization of two Zroxides and one Fe oxide. From the outgassed amounts of water and nitrogen the H2O/N2 molar ratio can be used to estimate an effective pore size in oxides.

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Ultra-High Vacuum Processing and Characterization of Chemically Functionalized Graphene

ECS Meeting Abstracts ◽

10.1149/ma2010-01/23/1191 ◽

2010 ◽

Keyword(s):

High Vacuum ◽

Ultra High Vacuum ◽

Functionalized Graphene ◽

Vacuum Processing

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Silicon Wafer Bonding: Effect of Wafer Surface Treatment on Interface Structure and Chemistry

Microscopy and Microanalysis ◽

10.1017/s1431927600037867 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 1074-1075

Author(s):

M.J Cox ◽

M.J. Kim ◽

Hong Xu ◽

R.W. Carpenter

Keyword(s):

Wafer Bonding ◽

High Vacuum ◽

Interface Structure ◽

Single Step ◽

Ultra High Vacuum ◽

Native Oxide ◽

Wafer Surface ◽

Step Process ◽

Bonding Effect ◽

Atomically Flat

The two most important characteristics of any surface considered for wafer bonding are cleanliness, surface smoothness and macroscopic flatness. Silicon wafers in the as-received condition have a native oxide on the surface several nanometers thick [1], Figure la shows that they also have a layer of hydrocarbons. While they are not clean, they are smooth. Our wafers were plasma or ion cleaned, chemically treated, and ultra high vacuum (UHV) thermal desorption annealed in different combinations to find the best method for providing smooth, contamination free substrates that will produce an atomically flat, chemically clean Si/Si bonded interface.The first approach was a single step process to remove the contaminants and then bond the clean wafers. Cleaning was accomplished by ion bombardment of the surface in an UHV chamber with base pressure 1x109 Torr. This ion cleaning chamber is connected between the UHV (2x10-10 ) bonding chamber and UHV (1x10-10) analysis chamber, allowing wafers to be cleaned, analyzed, and bonded without breaking vacuum [2].

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