9.3 Control of the Experiments

The devices probed in our experiments are either packaged into custom ceramic packages or directly measured at the wafer level. For the packaged devices, special furnaces are available which allow to contact the chips and to apply a defined temperature profile. For the wafer-level experiments a semi-automatic probestation, which allows to automatically move the contact probes between different transistors, is used. To control the interaction between all the individual components, a jobserver has been designed, see Figure 9.19.

The jobserver is responsible for device selection in case of a semi-automatic probestation, and also controls the device temperature via the power-supply of the furnace or the thermo-chuck of the probestation. Furthermore, a queue control has been implemented which allows to submit jobs any time which will be sequentially processed. As BTI measurements can last several months, the setup is protected against power supply interruptions using UPSs, which are monitored by the central jobserver. A very convenient feature of the jobserver is the E-Mail notification feature which provides the user with information regarding successful or failed measurements.