# Presentation: 004972

## Extending the Temperature Range of Electronics for Spacecraft

- Randall KirschmanNASA/JPL14-16 May 2003Pasadena, California

- Extreme Environment Technologies for Space Exploration

## Why are we here?(Why are we having this meeting?)

## “Very Little of the Solar System (or the Universe) Is at Room Temperature.”

## How do we approach this situation?

## Traditional approach:

- Send “room-temperature” to the remote site for the electronics.

## Spacecraft

## Spacecraft

## Drawbacks of Using Conventional Electronics

- Insulation
- adds volume and weight
- reduces maneuverability
- limits operating time (passive)
- Heating/cooling (active)
- uses large amount of power
- adds control complexity
- disturbs environment
- reduces reliability
- Sometimes impractical

## Another approach:

- Let the spacecraft electronics operate at the temperature of the remote environment.

## Spacecraft

## Benefits of LT or HT Electronics

- Reduce mass & volume
- Reduce power requirements, increase efficiency
- (Improve performance)
- Reduce complexity
- Increase mission lifetime
- Improve maneuverability
- Increase *overall* reliability
- Less disruption of environment      (size and waste heat)
- Enable missions

## Relatively unknown and unproven technologies
Limited experience
Limited background information
New effects
Electronics may be less reliable (esp. HT)
Need more extensive qualification
More difficult design
Reduced performance (esp. HT)
Lack of specified components
Complete range of components not available

- Limited experience
- Limited background information
- New effects
*Electronics* may be less reliable (esp. HT)
- Need more extensive qualification
- More difficult design
- Reduced performance (esp. HT)
- Lack of specified components
- Complete range of components not available

- Difficulties of LT or HT Electronics

## Alternative Approaches

- Part extreme temp &    part conventional Temp     (temperature partition)
- Intermediate temperature

## Low T or High T Electronics:What Is PossibleandWhat Is Practical?

## Electronics Temperature Capabilities

- Active devices (usually semiconductor)
- Passive components
- Power sources (especially batteries)
- Assembly & packaging (putting it all together)

## Low Temperature

##  Si Bipolars: BJTs

## Bipolars: Si BJTs, Ge BJTs, SiGe HBTs

## Ge BJT: –269°C (4 K)

- PNP; horiz: 0.5 V/div; vert: 1 mA/div; base current step: 0.1 mA (liquid helium); beta ~ 15 (RT beta ~ 70).

- R. R. Ward, unpublished data.

## Low-Temp Electronics in Spacecraft

## High Temperature

## Passives and Packaging

- Low temperature
- relatively easy
- with care in materials selection and design can go to ~0 K
- High temperature
- more difficult
- melting, decomposition, interactions
- depends on packaging “level,” component types, . . .
- ~200–500°C
- Low or high temperature
*primary difficulties are large-value capacitors **    (electrolytic, ceramic) and batteries** *
- Depends on requirements
- allowable TCR, TCC, . . .
- aging, lifetime

## The Overall Picture

- Temperature is not the only factor/stress
- Examples of additional factors
- Time
- Radiation
- Acceleration, vibration, shock
- Pressure
- Corrosive ambients
- Temperature does no act in isolation
- Interaction between temperature and other factors is often complex

## The Overall Picture

- Temperature is not the only factor/stress
- Examples of additional factors
- Time
- Radiation
- Acceleration, vibration, shock
- Pressure
- Corrosive ambients
- Not acting in isolation
- Interaction between T and other factors is often complex

## Aging Rates

- Arrhenius relation:  Rate  exp (–Ea/kT)
- Ea = Activation energy
- k = Boltzmann’s constant
- T = absolute temperature

## Arrhenius - One Process

## Arrhenius - Three Processes

## Extrapolation (or Interpolation) - risky
Assumptions:
Dominant mechanism remains so for all temperatures
Dominant mechanism remains so for all times

- Assumptions:
- Dominant mechanism remains so for all temperatures
- Dominant mechanism remains so for all times

## Degradation at Low Temperature?

## Degradation at Low Temperature

- Most processes are thermally activated, essentially absent
- Corrosion, electromigration, interdiffusion, ...
- Charge trapping
- High electric field
- Radiation
- Can be reversible
- Warming can de-trap (“anneal”)

## Temperature Effects

- Too much thermal energy (HT)
- Decomposition, corrosion, electromigration, interactions, interdiffusion, restructuring, . . .
- Excessive leakage currents
- Too little thermal energy (LT)
- Freeze-out (semiconductor devices, capacitors, batteries)
- Charge trapping

## “Often temperature (thermal energy) works against you, but sometimes it works for you.”

## Summary/Conclusions

- Extending the temperature range of electronics has benefits for spacecraft
- Electronics is capable of operation at extreme temperatures in practice as well as in principle
- In designing electronics, all the factors need to be taken into account (time, radiation, . . . )
- The interaction of temperature with other factors (e.g. time) can be complicated
- Thermal energy can work for us or against us

## EEE Meetings

- This meeting - future?
- NEPP usually yearly
- ECS LTE usually odd years (October 2003 in Florida)
- WOLTE even years (June 2004 in Netherlands)
- HITEN usually odd years (July 2003 in Oxford)
- HiTEC usually even years (2004?)
- ISAS yearly (Spring in Japan)
-  Check The ETE Web Site

## www.ExtremeTemperatureElectronics.com