Saturday, June 30, 2012

MEMS Fabrication Processes

The techniques utilized in MEMS fabrication borrow from techniques established for the integrated circuit industry, but they have been extended to include production of mechanical components. There are three elements in the conventional processing of silicon wafers. These elements are deposition, etching and lithography. Let's take a good look at them.


Deposition answers the challenges within the basic building blocks of MEMS processing, particularly with the ability of depositing thin films or layers of material. Here, it is to be assumed that any thin film will have a thickness from a fraction of a nanometer to several micrometers. This film material can be etched locally using various processes in the etching and lithography departments.

Chemical deposition or specifically the chemical-vapor deposition (CVD) functions on the principle that initiating surface chemical reactions within controlled atmospheres will result to the deposition of various reactions on heated substrates. In all essence, CVD is a process that requires high temperatures. It is categorized by the following: atmospheric - pressure (APCVD), low pressure (LPCVD), plasma - enhanced (PECVD), of which it also encompasses high - density plasma (HDP - CVD).

Epitaxy is a deposition method that grows a crystalline silicon layer on top of a silicon wafer with a different dopant type, including its concentration.


Etching technology can work on isotropic (omnidirectional) or on anisotropic (directional) principles. Isotropic etchants functions by etching through all directions uniformly, which would then result into rounded cross-sectional features. Anisotropic etchants by contrast, etches in various directions over others, which would result to abnormal cavities or trenches delineated by the flat and well-defined surface. It does not need to be perpendicular to the wafer surface.

Etch rates and its overall speed must be fast enough to be effective and viable for production. It must be controlled as well, though it is not location dependent.

Within the etching industry, the wet etching process is probably the simplest to achieve. All that the activity requires is a liquid solution container that dissolves the material in question. Complications arise though, since the person doing the etching needs to wear a mask. This mask must be durable enough no to dissolve during operation

Another method, called Reactive ion etching places the substrate inside reactors where it will be introduced to several gas types. Plasma will also be struck within the gas mixture via an RF power source, which breaks the gas molecules lingering within into ions. These accelerate and then reacted towards the etched surface material, which would then form into another gaseous material. This chemical process takes place in reactive ion etching.


This particular MEMS technique involves the following steps: application of photoresist, which is actually a standard layer with photosensitive emulsion; an optical exposure of the mask printed into the photoresist; and an aqueous solution immersion dissolving the exposed photoresist. The third type also renders the latent image created visible.

The field of micro devices is still relatively new. MEMS fabrication advancements will change the world in which we live in many ways. These micro devices are well capable of achieving great mechanical feats on a macro scale. This is the future.

Jessica entered the Semiconductor Manufacturing field in 1998 and held positions at Integrated Micromachines and Xponent Photonics prior to founding Rogue Valley Microdevices, specializing in silicon wafers and establishing it as one of the leading MEMS fabrication and manufacturing facilities.

Monday, June 18, 2012

IP Camera - Advantages Over an Analogue Camera

The Main Advantages of an IP Megapixel Camera over an Analogue Camera

    The megapixel IP camera will enable you to zoom in on certain areas of the picture before the point of interest pixellates.
    The camera will cover a larger area, e.g. a 1.3 Megapixel camera will cover 3 times the area of a standard analogue camera
    The recorded picture can be digitally zoomed without the picture being distorted to obtain face and number plate recognition

Quality Resolution Chart for Cameras

    2 CIF - 704x288 = 202,752 pixels
    VGA - 640x480= 307,200 pixels
    D1 - 720x486 = 349,920 pixels
    4 CIF - 704x576 = 405,504 pixels
    1.3 Megapixel - 1280x1024 = 1,310,720 pixels

Top IP Camera Manufacturers in the World are:


IP Cameras - Some Factors to be considered

    How many megapixels in the IP camera
    What size CCD is in the camera, it is normally a 1/4", 1/3" or a 1/2". The 1/2" is the highest quality and the 1/4" is the lowest quality
    Does the camera have Infra red built in or do you need to provide extra lighting (infra red or security flood lights etc)
    Is the camera compatible with your network video recorder
    Do you want the camera to have an SD slot for recording locally on to an SD card?

In a lot of cases the quantity of Megapixel Cameras required in an installation will be less than when using analogue cameras. Garage forecourts are now opting for a 1, 2, or 3 megapixel IP camera mounted on each side of the Garage forecourt to read the registrations for up to 4-6 vehicles. Previously the analogue cameras would have been deployed over each pump. This is always the case when trying to obtain a vehicle registration plate number.

Number Plate Recognition Test

We have carried out tests on Megapixel cameras to test them for number plate recognition at both day time and night time. We used a 2 megapixel Vivotek Camera mounted on the corner of a garage approximately 35m from the point of interest at the gate. The car is captured in the image at the gate, at distance we cannot read the registration plate. However, when we digitally zoom in on the car using an Avermedia NVR, the registration plate can clearly be seen and there is no blurriness of the image.

Similarly, we carried out a night time test using the same Megapixel IP Camera. The test was in a rural area where there is no street lighting or ambient lighting whatsoever. A small Infra Red (IR) illuminator has been mounted underneath the camera. Even with the full headlights on, the registration plate is perfectly readable when we zoom in on the footage.

Wireless IP Cameras

With the advent of IP cameras it has become easier and more cost effective to transmit video signals wirelessly for an IP camera. A wireless device can be located at each IP camera and normally one device will receive the video signal for up to 3 or 4 cameras and transmit on to a switch and connect into a NVR (Network Video Recorder). Unlike wireless analogue cameras line of sight is not required and a signal can be transmitted for over 2-3 kilometres.

AlertWatch specialise in the installation and supply of CCTV Systems (Including IP Cameras) throughout Ireland and the UK. Should you require any information, support or help on any aspect of CCTV surveillance we would love to hear from you.

Saturday, June 9, 2012

5 Great Android Apps for Amazing Video Conferencing

Video conferencing makes our lives easier. Connecting with people from school and business has also been made possible because of video conferencing. In line with this, Android also allows its devices to do just that. In no particular order, here are 5 Great Android apps for Amazing Video conferencing:

1. Qik Video Connect

The Android Qik's interface is different with that of its iOs counterpart. The Android version has four blocks on its screen each representing a certain function with its description. Its functions include Video Chat, Record and Share, Video Mail and Video Gallery. Although the Android version differs with the iOs version in its appearance, both have the same functionality.

Aside from its Video Chat function, another thing which you may find interesting is the Video mail. It's just like the Voice Mail but this time, it uses video. An advantage of the Video Mail is that the quality of the video is better than that of the live video chat since it is pre-recorded. The bad news is that you may not be able to use this service for free after June 1 since they will be charging an annual fee for this service.

With Qik, you can also upload your videos to the web and share them via email and SMS. Although Qik has good features, it may not have the best video chat experience. Right now, however, Qik is one of the best options among Video Conferencing Android apps.

2. Tango

The good thing about Tango is that it allows it users to have a cross-platform video chat. That means you can have a video chat with a friend using an iOs even if you're on Android-very cool indeed! Although Fring has this capability, Tango scores more points when it comes to video quality and ease of use. With Tango, one can also make calls over 3G and 4G networks as well.

Finding your friends using Tango is also made convenient by this app. Tango can search through your Android or iPhone Address book for friends who are on Tango and adds them into the app's contact list. Also, setup of this app is quite easy.

3. Fring

Fring is user-friendly. Its interface is neat and not cluttered. Even a first-time user wouldn't have a problem getting to know the app. Video Quality is good although not as good as FaceTime (iPhone). Its audio still has more room for improvement. The good thing, though, is that it can be downloaded from the Android website for free.

4. Knocking Live Video

Knocking Live Video lets its user share live video from his phone to another one's. This Video-sharing app used to be available only in the iPhone. Now, it's in Android-good news for Android enthusiasts! This is a cross-platform app which means that an Android user can share live videos to a family or friend who's using the iPhone. It's one of the most popular social network apps today and you can download this app for free.

5. Skype

Skype is undeniably one of the best in VoIP apps around. Unfortunately, Android Skype doesn't have video conferencing with the exception of 4G phones. A lot are hopeful though that this service would extend to non-4G phones in the near future.

Danny writes for Android Tablets Fanatic and is available to write guest posts for your blog/website so just contact him if you're interested in free content for your website.