JFETs and Circuits …

18 11 2010

The JFETs are back from being diced and so it’s time to move up a gear. The first challenge is to simulate the behaviour of our eventual circuits, so having spent hours and hours testing the devices, we’ve dropped the parameters into SPICE. We’re pretty happy with the results, as can be seen below…

Silicon Carbide JFET data SPICE

SPICE model for SiC JFET

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Graphene just doesn’t bond …

12 11 2010

From what we have been told, people putting contacts down onto graphene samples are having issues with wire bonding. This is a serious problem, as without the ability to put wires on, it’s difficult to connect it up to the rest of the circuit and do something interesting with it. Testing in the lab is not going to be affected, as everybody makes contacts with probes, but this is only useful for short term tests! Longer term, the ability to connect the devices up with wires is an absolute necessity…

Recently, we’ve had this problem as well and we’ve made a discovery.

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12 11 2010

It’s been chaos round here lately and so this is the first post for a while. I’m busy trying to write an application to the EPSRC Basic Technology Call, which closes on the 24th of November, as well as decide on my research strategy for the next five years. There’s also a lot of interest in the call from the UK Space Agency about putting small payloads on a small satellite, UKube, planned for launch in December 2011. We’re looking to bid to get some of our stuff onboard, but the deadline is the same day as the EPSRC bid. The next opportunity in the mix, is an advert for the next silicon carbide conference, in June next year. The WASMPE/Hetero-Sic conference is going to be held in Tours, which sounds really nice, in June 2011. The best bit, is that you can get there on the train, and avoid all the hassle of airports.

During all this, the JFETs have been in further testing and we now have some 800 functional devices, some of which have gate leakage below 100pA. They are now being diced out before we get them packaged up for long term testing and circuit construction. At the same time, Ben’s gas sensors have now been characterised (at room temperature) and are also off to be diced at the Scottish Microelectronics Centre.

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