 Efficient detection of general paging messages in poor signal to noise environments |
| The invention is directed to methods of and an apparatus for detecting general paging messages. In ... |
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| Radio telephone |
| In accordance with the present invention there is provided a radio telephone operable in respective ... |
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| Portable radiotelephone and holder for mounting within a vehicle |
| Therefore, the present invention is made in view of the afore-mentioned disadvantages and an object ... |
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| Telephone dispenser with compact cord guide |
| Accordingly, it is an object of the present invention to provide a telephone handset that functions ... |
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| Power limiting circuit for radio communication device with a retractable antenna |
| The present invention relates to power control for a radio communication device having a ... |
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| User interface for a radio telephone |
| In accordance with the present invention there is provided a radiophone comprising a user interface ... |
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Method of controlling multi-species epitaxial deposition
| Details |
Inventors: Pinsukanjana, Paul Ruengrit; Gossard, Arthur Charles; Jackson, Andrew William; Tofte, Jan Arild; English, John H.;
Assignee:
Primary Examiner: Evans; F. L.
Assistant Examiner:
Attorney, Agent or Firm: Foley & Lardner
An integrated dual beam multi-channel optical-based flux monitor and method of monitoring atomic absorption of a plurality of atomic species during epitaxial deposition. Light from multiple sources is simultaneously passed through a region of deposition of material such that atomic absorption takes place. The light that passed through the region is then compared to light in a reference arm that did not pass through a region of atomic absorption. From this comparison the deposition of an epitaxial layer can be carefully monitored and controlled. |
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced.
It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
The schematic diagrams for two versions of the invention are shown in FIGS.
1 and 4, respectively.
These FIGS.
are specific to a three-channel optical based flux monitor (OFM) which monitor Al, Ga, and In simultaneously.
The same principle may also be applied to a monitoring system with more or fewer channels and with other elements.
Because each deposition system is unique, different optimization criteria have to be considered for each specific application.
The description below is optimized for a solid source GEN II MBE system configured for III-V semiconductor material system, i.
e.
, AlGaInAs.
The typical deposition rates are in the range of 10.
sup.
-1 to 10.
sup.
0 monolayers per second.
The devices are deposited under As over-pressure and with unity sticking coefficient for the group III elements.
However, one skilled in the art would recognize how to correct for non-unity sticking coefficient.
In the first embodiment, as shown in FIG.
1, the light sources 10a-c are hollow cathode lamps (HCL).
Alternatively, the light sources 10a-c can be laser diodes or laser systems.
Light source 10a is an Aluminum (Al) source and therefore it emits light with frequencies corresponding to Aluminum.
Light sources 10b and 10c are Gallium (Ga) and Indium (In) sources, respectively.
The HCL's can be operated under constant current or under constant light output mode.
The light from the light sources 10a-c is filtered by narrow bandpass filters 12a-c, respectively, resulting in a bandpass output corresponding to each light source.
Typically, for Al, Ga, and In, the narrow bandpass region is centered at corresponding emission lines which are at 395 nm, 417 nm, and 410 nm respectively with a typical bandwidth of 10 nm
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Ring Tones 
