Specifications 

This listing is for a 8-inch silicon wafer that was manufactured as a power device(IGBT) but has failed the final step of the manufacturing process. These silicon wafers are non-functional. Please note the wafer you receive may differ slightly to the one in the listing as there are many variations.  

This is a great educational product to show students what a silicon wafer looks like in person. 

Technical Details

The reason these wafers are thin and flexible is they have been ground thin to 150 microns after manufacture. They are originally 650 microns thick. They have to be made this way as they would be too easily damaged whilst being processed. 

They are made of silicon. As these are power devices they are ground thin to enable the heat generated in operation to be transferred to the heatsink. These wafers were made my International Rectifier (now Infineon) they are about 10 years old. If you search the part number you will find the data sheet. "Infineon 65C6070" This is a high power MOSFET these are used in switch mode power supplies. It can switch 650V at 35A Each die on the wafer would sell for about £15.00 each, so one scrap wafer is quite a loss. 

They are normally made in batches of 50 wafers, so a scrap lot results in the loss of several thousand pounds. These wafers have failed during probe test. The back of these wafers are coated with metal, first its sputter coated with Titanium, then Nickel, and finally Silver. This is to allow it to be soldered to the copper heatsink of the device enclosure.

If you search for "Varian 3290" you can see the machine this is done on. I specialise repairing these machines, hence the supply of scrap wafers. If you search for "sputtering" you can read about this process of depositing metals in a vacuum system. The device IGBT/MOSFET is a three terminal device. The connections are source C gate and drain E. 

When the gate is biased to around 3 volts it causes conduction between the source and drain. The "on" resistance is very low allowing very high switching currents. The larger IGBT devices which are used on train engines and the national grid are made using a whole 8 inch wafer for one device. This will switch several thousand amps very efficiently.

Postage

This item comes specially packaged between 2 pieces of laser cut hardboard to prevent snapping of the wafer. These items are very fragile and can break extremely easily

Royal Mail 2nd Class Signed For : £0.00

Royal Mail 1st Class Signed For : £1.99

Postage options are available at checkout 

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