3.4.4. Models for specific component types#

The reliability.space approach for EEE items provides data about models for reliability predictions for some EEE components which have no validated models. The specific component types refer to the components which are not included in the EPPL [BR_EEE_9] or which have no validated models.

3.4.4.1. Models from the Telcordia SR-332 handbook#

Five opto-electronic components usually used in space applications have no models available in the FIDES guide. These five components are the phototransistor, the photodiode, the laser diode, the laser detector and the laser transceiver. A possible way forward is to use the models provided by the Telcordia SR-332 handbook [BR_EEE_25]. However, these models of opto-electronics components have been developed for communication systems on ground. They have never been assessed for space applications and a preliminary investigation and assessment are required to use them for space applications.

Proposition

It is proposed to user to apply these models in order to close the gap in covering for these types of components.

3.4.4.2. Models from the PISTIS project#

The PISTIS project is a collaborative study managed by Thales and co-founded by DGA, an entity of the French Ministry of Defence. 14 companies and universities contribute to this study. The main purpose is to improve the knowledge of some innovative components and emerging technologies regarding their reliability and wear-out after long-term ageing. Depending on these results, the second step is to create reliability prediction models for these innovative components.

The results of the PISTIS project have been released after the development of the present methodology. These have been included in the 2021 issue of the FIDES guide.

Proposition

The reliability.space consortium has not been able to apply the models presented in this section so it is only proposed to the users to apply these models for their designs.

3.4.4.2.1. DSM components#

DSM (Deep Sub Micron) components are a generic denomination for electronic components for which the size of engraving is smaller than for current commercial components. No clear standard is defined for the size limit under which a component is considered as a DSM, but generally this limit is fixed to around 60nm. These components are interesting for space applications because they have a higher power of calculation and can store more data while requiring less room on the board. With the reduction of size, failure mechanisms can generally occur with a higher probability and some of the failure mechanisms which are quite seldom can occur on DSM components with a higher frequency. A challenge for the future is to better identify these failure mechanisms and this is an objective of the PISTIS project.

The PISTIS has performed perform long duration tests in order to get failures on tested DSM components, to identify the failure mechanisms and then to perform a validated model for the 2021 issue of FIDES. The following tests have been realised:

  • Test in hot temperature of +25°C, +90°C and +115°C on FPGA: important drifts after 5 000 hours have been noticed on most of the components due to the Negative Bias Temperature Instability;

  • Test in low temperature of -30°C on FPGA: low drift has been noticed on some of the components;

  • Test in hot temperature of +85°C and +125°C on NOR memories of static retention: some components have shown failures during storage at +125°C with failures located on intermetallic of copper bondings;

  • Test in hot temperature of +85°C and +105°C on NOR memories of read / write / erase operations: all components have shown failures at +105°C;

  • Test in hot temperature of +85°C and +125°C on NAND memories of static retention: no component has shown failure during storage at +85°C and +125°C;

  • Test in hot temperature of +25°C, +85°C and +105°C on NAND memories of read / write / erase operations: all components have shown failures at +85°C.

The model proposed in the 2021 issue of FIDES focusses on the main changes vs other Integrated Circuits, ie the wear out failures type.

The BTI mechanism has been identified as the main contributor for degradation of DSMs.

  • Up to 100°C junction temperature with a duty cycle of 100%, the FR related to BTI is negligible -> it remains below 0.1 FIT after 50 years of use.

  • Above 100°C junction temperature, it does become significant.

The recommendation from the FIDES consortium is then:

  • Under 100°C and with \(V_{\text{applied}}/V_{\text{nom}}\) < or = 1.05 -> the FR associated to BTI can be negliged

  • Above 100°C and with a ratio \(V_{\text{applied}}/V_{\text{nom}}\) < or = 1.05 -> the impact needs to be assessed following at table provided in the guide.

  • Between 100°C and 125°C and with a ration \(V_{\text{applied}}/V_{\text{nom}}\) < or = 1.10, a wear out law is provided for inclusion for the FR calculation.

A model is also provided for 3D technologies

3.4.4.2.2. GaAs component#

GaAs components are used mainly for microwave and radio-frequency applications. The use of these components is quite recent and convenient for space applications because they have some interesting properties in high frequencies.

The FIDES guide includes models for GaAs components for radio-frequency applications. These models are applicable for low power transistors and high power transistors. The model is similar for both categories of transistors, but the basic failure rates are different. FIDES is continuously increasing its database with the tests and feedback from GaAs components and data from manufacturers. Even if the quantity of the available data is significant, the intention is to merge these two basic failure rates into only one category that gathers all types of GaAs transistors. Otherwise, a synthesis of data from manufacturers of GaAs components has provided an activation energy of 2.0eV for GaAs components dedicated to radio-frequency. The next step is to realise a model based on this information.

Note

In the 2021 issue of the FIDES guide, some update (Pi Process HF/RF, \(\lambda_{\text{OTH}}\)) has been provided for the HF/RF GaAs models, providing in particular a new version of \(\lambda_{\text{TH}}\) that would require some modelling in order to compare it to test data and define its applicability.

3.4.4.2.3. GaN components#

GaN components are used mainly for power applications, optical applications, microwave and radio-frequency applications. These components provide great opportunities because they allow mixing components of different technologies for specific system architectures.

The 2009 issue of the FIDES guide does not include GaN components for power and radio-frequency. In order to provide models, the PISTIS project is currently on the way to perform long duration tests in order to get failures on their tested GaN radio-frequency components to identify the failure mechanisms and then to derive a validated model for the 2021 release of FIDES. A synthesis of data from manufacturers of GaN components has provided an activation energy of 1.6eV for GaN components dedicated to radio-frequency. Tests have been performed with a total duration of more than 60 000 hours at a high temperature of +120°C. Components are still functioning and no failure has been detected yet. The next step is to continue the tests with the aim to get some failures or observations of parameter drift and to identify the failure or wear-out mechanisms. Afterwards, the basic failure rates of these GaN components will be estimated with data issued from publications and academic studies.

The models for both GaN MMICs and GaN transistors are introduced hereafter:

  • Update of the Pi Process HF/RF to include questions applicable to the GaN technology

  • The general formula is the same as presented for HF/RF GaAs components

  • \(\lambda_{\text{OTH}}\) for GaN are provided in the following tables:

Table 3.4.199 Basic failure rates \(\lambda_{\text{OTH}}\) for GaN RF/HF components.#

Type

\(\lambda_{\text{OTH}}\)

GaN HF/RF transistor /diodes

0.3033

GaN MMIC

0.3033

  • \(C_{\text{sensitivity}}\) for GaN are provided in the following tables:

Table 3.4.200 Induced \(C_{\text{sensitivity}}\) factor for GaN RF/HF components.#

Type

\(C_{\text{sensitivity}}\)

GaN HF/RF transistor /diodes

6.9

GaN MMIC

6.9

Note

The use of GaN power FETs had not been considered at the beginning of this project but it is actually currently used in designs for space applications. A model now exists in FIDES 2021 after the PISTIS models have been developed, so the user can apply this model. But like for the rest of models from PISTIS, these have not been analysed or applied in the frame of this study.