a. If one of the technologies identified in Table 7‑1 is used in spacecraft and planetary-mission systems, the potential TID level and effects shall be analysed.
NOTE 1 Technologies in Table 7‑1 are susceptible to TID. This is not exhaustive and other parameters can be important and result from worst-case analysis.
NOTE 2 As specified in Clauses 8, 9 and 10, calculation of cumulative damage due to non-ionising energy loss and single event effects and detector background is also mandatory for many of these components, such as those based on bipolar junction transistors or optoelectronics.
Table 7‑1: Technologies susceptible to total ionising dose effects
|
Technology category |
Sub categories |
Effects |
|
MOS |
NMOS PMOS CMOS CMOS/SOS/SOI |
Threshold voltage shift Decrease in drive current Decrease in switching speed Increased leakage current |
|
BJT |
|
hFE degradation, particularly for low-current conditions |
|
JFET |
|
Enhanced source-drain leakage currents |
|
Analogue microelectronics (general) |
|
Changes in offset voltage and offset current Changes in bias-current Gain degradation |
|
Digital microelectronics (general) |
|
Enhanced transistor leakage Logic failure from |
|
CCDs |
|
Increased dark currents Effects on MOS transistor elements (described above) Some effects on CTE |
|
APS |
|
Changes to MOS-based circuitry of imager (as described above) – including changes in pixel amplifier gain |
|
MEMS |
|
Shift in response due to charge build-up in dielectric layers near to moving parts |
|
Quartz resonant crystals |
|
Frequency shifts |
|
Optical materials |
Cover glasses Fibre optics Optical components, coatings, instruments and scintillators |
Increased absorption Variation in absorption spectrum (coloration) |
|
Polymeric surfaces (generally only important for materials exterior to spacecraft) |
|
Mechanical degradation Changes to dielectric properties |