Vacuum Annealing

A vacuum anneal will clean your chips of organics, leave you with better contact resistances (we sometimes see 80-95% decreases), and can partially restore a leaky gate oxide. The process works with platinum and gold electrodes. Be aware: gold electrodes seem to have less adhesion to SiO2 following a vacuum anneal. This can be seen when contacting the electrodes in the probe station. Be aware: vacuum anneals sometimes create ~μm sized 'holes' in your electrodes. This effect is likely due to photo resist residue trapped under the electrodes. So far, the holes haven't affected device performance.

Substrate heater

We've used a Q-series panel heater from Solar Products, Inc. These are not actually substrate heaters, they are multi-purpose heaters used for drying paint & other applications. For that reason they are much cheaper (~$385) than 'real' substrate heaters (~$1,500). To make them vacuum compatible, request that they do not put in the fibrous insulating material in the back. According to Chris Tasker, they are good in vacuum up to ~900 C.

We've used a part that was custom-made for Chris Tasker in the past (part #: OSU-3-3-120-I). The specs are 3x3x3”. High purity quartz for clean room applications. It is designed for 120 volts, and it produces 540 watts at full power. It is a stainless steel case, and non-outgassing insulating blanket is contained between two pieces of quartz – the face plate and a backup plate. This is a design that has been used in many clean room applications.

It has two 1/4 - 20 stainless steel mounting studs on the back so that it can easily be fixed in place. There are two stainless steel terminals exiting the back of the heater and you would connect your leads to those terminals. The heater can be run either face up or face down.