2

Radiation

The technology of STMicroelectronics Rad-Hard rectifier’s diodes is intrinsically highly resistant to radiative

environments.

The product radiation hardness assurance is supported by a total ionisation dose (TID) test at high dose rate and

a single effect event (SEE) characterization.

2.1

Total dose radiation (TID) testing

Diodes are considered as intrinsically immune to Total Ionization Dose (TID) up to at least 300 krad(Si) as per

ESCC-Q-ST-60-15C.

ST has characterized the STTH40200CHR in TID up to 3 Mrad(Si) on 21 parts issued from two different diffusion

lots, packaged in SMD1, 7 parts unbiased, 7 parts reverse biased and 7 parts forward biased.

The irradiation has been done according to the ESCC 22900 specification standard window i.e. high dose rate

(0.36 to 180 krad(Si)/hour ).

Both pre-irradiation and post-irradiation performances have been tested using the same circuitry and test

The key parameters were measured four times:

•

Before irradiation

•

After irradiation at final dose 3 Mrad (Si)

•

After 168 hrs at room temperature

•

After 168 hrs at 100 °C anneal

All parameters stay within specification after each steps, supporting the claim that the product sustains 3

Mrad(Si). However, in absence of TID test on each wafer lot, the product is not ESCC qualified at this radiation

level.

2.2

Single event effect

The Single Event Effect (SEE) relevant to power rectifiers are characterized, i.e. the Single Event Burnout (SEB).

The tests are performed as per ESCC 25100, each one on 3 pieces from 1 wafer at room temperature.

The accept/reject criteria are :

•

SEB (destructive mode):

The diode is reverse biased during irradiation. The test is stopped as soon as a SEB occurs or when the

reverse leakage current is above the specification or when the overall fluency on the component reaches

1E7 cm².

•

PIST (post-irradiation stress) test:

After the irradiation, a stress is applied to the diode in order to reveal any latent damage on the irradiated

devices.

Type

Conditions

Result

Total ionisation dose

Charaterization of 2 wafer lots at 22 +/- 3°C

High dose rate 7 reverse biased + 7 forward biased + 7 unbiased

Immune up to 3 Mrad(Si)

Single effect burnout

LET : 62.5 MeV.cm/mg

No burnout

STTH40200CHR

Radiation

DS12525 - Rev 5

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