Proton Irradiation Damage in a 2N2222 Bipolar Transistor

radex18.in : Proton Irradiation Damage in a 2N2222 Bipolar Transistor

Requires: Athena Atlas
Minimum Versions: Athena 5.23.0.A Atlas 5.25.4.A

This examples demonstrates the simulation of proton irradiation damage in a 2N2222 bipolar transistor.

The 2N2222 bipolar transistor is one of the most common devices found in satellites, and is a standard benchmark for devices to be tested against. There are numerous manufacturers of this part number. In this example, specifications were taken from an example made by ON Semiconductor. The ON semiconductor device exhibits a base/emitter breakdown voltage of 6 Volts and a collector/base breakdown voltage of 70 Volts. The floating base collector/emitter breakdown voltage is 40 Volts. The minimum gain was specified at 100 when Vce=10 Volts.

Not shown in this example, the base doing was simulated such that Veb=6 Volts with solid solubility doping in the emitter. Once this base doping was known, the colletor doping was set such that Vcb>70 Volts with the previously extracted base doping. The base width was set such that the current gain was greater than 100 consistent with a floating base Vce>40 Volts.

Once the DC characteristics were satisfactory, proton irradiation was simulated with a proton fluence of 1e11, 1e12 and 1e13/cm2, as set in the radiation statement using the flence parameter. The physical damage created by the proton irradiation is caused by the Non Ionising Energy Loss (neil) parameter, since it is presumed that the ionising part of the energy loss mechanism occurs by elastic scattering, and therefore creates no damage. Also set is the scaling factor parameter dam.proton and the energy of the in-coming protons.

For each fluence simulation, the simulator creates bulk defects in proportion to the specified fluence, whose capture cross sections are specified in the defects statement, together with the fluence.model switch parameter. The other defects statement in the input file is there because in this example, we are using a polysilicon emitter doping source, so a further defect statement is required to specify the defects in the polysilicon which obviously existed prior to irradiation.

To load and run this example, select the Load button in DeckBuild > Examples. This will copy the input file and any support files to your current working directory. Select the Run button in DeckBuild to execute the example.