応用物理学会・先進パワー半導体分科会
第 10 回研究会テキスト

人工衛星に使用するパワーデバイスの宇宙線耐量
Failure rate calculation method for power semiconductors for space application

大村 一郎
Erdenebaatar Dashdondog
九州工業大学、北九州市若松区ひびきの 2 番 4 号（〒808-0196）
omura@ele.kyutech.ac.jp
概要
パワー半導体の高性能化が進むにつれ、パワー半導体の宇宙線破壊が問題となり、1990 年代半ばに詳細に研究された結果、実験的に得られた設計カーブにより高信頼なデバイスの設計が可能になった。
しかし最近、国際宇宙ステーションや人工衛星などの宇宙環境で用いる機器の消費電力が上昇し、電源の高電圧化が検討されているなかで、改めてパワーデバイスの宇宙線破壊が問題になってくる可能性が出てきた。
前述の地上でのデバイス利用を前提とした宇宙線破壊現象の解析では、地上での実験により検討を行うことができるため比較的容易に故障率の計算ができるようになっている。ところが宇宙利用の場合、高エネルギー粒子のエネルギーに対する確率分布（スペクトル）が異なるため、地上での実験結果を活用することができない。このため全く新しい、汎用的な故障率計算方法の確立が必須である。
本研究では、故障率の汎用計算式を導出し高エネルギー粒子のフラックス、高エネルギー粒子が発生する電荷の分布関数、さらに電荷が引き起こす破壊、の３つの観点から定式化を行い、それぞれの関数を人工衛星に関する研究論文、核物理に関する論文、さらに TCAD による破壊シミュレーションを組み合わせで求めた。さらに提案式で実際に低軌道人工衛星での 3.3ｋV PiN ダイオードの故障率を計算した。
今回提案した手法では、パワーデバイスで初めて宇宙線破壊断面積（SEB cross section）の計算を可能にし、一度この関数が求まれば、あらゆる高エネルギー粒子のフラックススペクトルに対して容易に故障率を計算することができる。将来、この式をさらにブラッシュアップし、広く汎用的に使われるようにパラメータ関数の基礎データを集め、計算プログラムの確立していきたい。
本報告は、下記の博士論文の内容を説明したものである。
Erdenebaatar Dashdondog, “Failure Rate Calculation Method for High Voltage Semiconductor Devices underSpace Radiation Environments” 九州工業大学 博士論文 2017

Outline
1. Introduction
Power Demand Increase in Stacecraft
Requirement of Bus Voltage Increase
Issues in High Voltage Power Device in Stacecraft

人工衛星に使用するパワーデバイスの宇宙線耐量

2. Cosmic Ray Induced failure in Power Device
Reason and mechanism

3. Failure Rate Calculation Formula for Stace Use Power
Device Design

九州工業大学大村一郎
ERDEEEBAATAR DASHDOEDOG

Protose of General Formula for Failure Rate Calculation
High Energy Particle (Proton) Flux Distribution Function
Energy (Charge) Detosition Probability Density Function
Device Destruction Charge for Attlied Voltage

4. Calculation Results for 3.3kV PiE diode for Low Orbit
5. Conclusions
1

Power Demand in SPACE

2

Power and Voltage in SPACECRAFT

Sputnik to International Space Station
SPUTEIK 1

International Stace Station

http://officenaps.com/exoticaspace-age/the-space-race/attachment/jacknitzsche/
http://i.dailymail.co.uk/i/pix/2015/03/02/263F8ADB00000578-2976216-image-m-38_1425325704906.jpg

Launch October 4, 1957
83kg; bit bigger than soccer ballElectrical Power~1W~3 weeks

Launch Eovember 20, 1998
419,455 kg; size of football field
Electrical Powerup to 120 kW~18 years

Power demand has been tremendously increased

Power Demand in Spacecraft

3

Power usage in Space application will
exponentially increase in future
Bus voltage increase !!

Ȃ ȂMeans1MW Ȃ 1000V
4Consequence of Power Increase

Vision and Goal of the Research

In order to reduce power loss:• Contribute to high tower devices’ reliability
in the future stace attlications

Thicker cable
VHigher bus voltage• Develot cosmic ray induced failure rate
calculation method for all kind of tower
devices in various stace environments

V• Demonstrate that trotosed method cangive failure rate of the high voltage device
at the low earth orbit environment.

In Order to Reduce power losses and weight, highvoltage power supply system will be required

56

Reason of the Failure

Single Event Failure Phenomena
Space radiation flux
ProtonCounts/m2/sec/MeV
httt://www.nasa.gov/mission_tages/msl/multimedia/tia16938.html

httts://voer.edu.vn/file/54639

Space Radiation
Effects

Total DoseSingle EventEffect

EffectPower
Semiconductor
Devices Failure
occurs inside devices
due to high energy
tarticles from staceeither stace orterrestrial.

AnodeCathode
P+N+i

Proton energy Et(MeV)

Cosmic Rays induced Single Event Effects
in Power Semiconductor Devices Giovanni
Buvatto Univervity of Cavvino ITALY78

Single Event Failure Phenomena

Single Event Failure Phenomena

Charge deposition probability distribution function for
300um silicon with proton energy as a parameter
Et

Burnout Condition based on avalanche phenomena

Detosited Charge Qd (C)

1/C
Et

Anode

Burnout

Cathode
P+

Anode

N+

CathodeP+

N+

Detosited Charge Qd (C)iSafeiAttlied Voltage (V)9Failure rate calculation formula!
%Ȃ!

" # $10Sources of Proton flux dataȂ
A: chit size

ChargePower Devices Physics
Based onT-CAD (SYEOPSIS)SIMULATIOE

Nuclear Physics
Based onStudy of LITERATURES&'()*+ ,- +. define/ 01

Astro Physics
Based on
SPEEVIS SIMULATIOE
Data of LITERATURES

The proposed formula successfully combines the models of the threephenomena
11
Detail of each model

The 90 tercent oftarticles of Cosmic ray
are trotons in the earth’s
radiation environment.

Source ofdata

1. SPENVIS

2. PAMELA

3. AMS

Methods

Simulation

On orbitExteriment

On orbitExteriment

ConsideredParticles

ProtonProtonProtonEnergy range

1-400MeV

1GeV-20GeV

20GeV-200GeV

Altitudes~700km~610km~400kmhttts://www.stenv
is.oma.be/O. Adriani, "PAMELA
Measurements of Cosmic-Ray
Proton and Helium Spectra,"Science, vol. 332, no. 6025,
pp. 69-72, Apr 2011.

Cosmic Rays from Rigidity 1 GV to
1.8 TV with the Alpha Magnetic
Spectrometer on the International
Space Station," Physical review
letters, vol. 114, pp. 171103-1, May
2015.

Plots

References12

1

Fitted functions of Proton flux

Charge detosition Probability!

&'()*+ ,- +. define
HIJKK L

234

5 7 8

9: 7<=

1GeV-20GeV troton flux in
LEO and its fitted function.
/PAMELA/> "<?897 88@

20GeV-200GeV troton flux
in LEO and its fittedfunction. /AMS/A BC

5 7 ?

9: ?<=

Proton flux probability is fitted for all the range of energy 1301
01

NK

797

F75

7 89

= F

:

F:

9OKKI FOSXKKI FXK!

" FD E!

M

B. Doucin, Y. Patin and J. P. Lochard, “Characterization of troton interactions inelectronic comtonents,” IEEE Trans. Eucl. Sci., Vol. 41, Eo. 3, tt. 593-600, 1994

7 D7
Ep [MeV]
2050100

The tair charge ise=1.6*10-19CHence
G=2.32*1013MeV/C

b1-0.2086-0.1187-0.0807

M B FDb0-3.2218-3.542-3.8617

The curve is fitted
from the graph usingsimple parameters
14

Detosited Charge Q[C]

Charge Avalanche Multitlication in Device

Fitted values for math. extression

NOe-h tair generationin Silicon requires
energyE ≈ 3.68 eV/tair"TU\(].-* ,- +.
definebyevt

VT YU

VAvalanche Multitlicationevt

3. Burnout

1. Safe• Combination of charge and voltage need to bedefined• Each point require transient TCAD simulation
for Avalanche• More than 100 points needed to be simulated•
Problem of simulation time

7 8 9@ :Fitted function is expanded to higher energy level

Deposited charge by proton [C]

1-400MeV troton flux data at
in LEO and its fitted function.
/SPEEVIS/7 D7 E"1516

Simulation Consideration

Electron current density distribution by voltage

Homogenous structure of diode makes it to be able toperform Cylindrical Simulations (Quasi-3D) instead ofordinary 3D simulation. =>reduction of simulation time

17The charge generation increases when applied voltage increases 18Destruction Charge Function

Device destruction curve due to charge

Generated charge [C]Generated charge [C]

3. Burnout
2. avalanche

1. Safe_Time^_ Idt

AdTimed"est(V)_^_ Idtb> "est(V)Current

Qd=Detosited charged

Current

Currentx
QA=Avalanche charge

_

QA=∞
Time

^_ Idt >>" #"est(V)$Destruction charge function

The safe area’s border defines destruction charge curve? Ȃ 7 97
" #9$

$ defined by fitting simulation result2019Failure rate calculation

Calculated Failure rate of 3.3kVdiode in Stace
3.3kV PiE diode, Proton incident energy range 1MeV-200GeV
Aluminum shieldaffects only lowenergy range" #$? Ȃ 7 97/',d\(* e'+*

97$

I ijk
Iiqr

fȂ

97

F75

7 89

= Fhijkhlmno p:F:

7 8 9@ :234

5 7 8> "<?897 88@

A BC

5 7 ?

9: ?<=

9: 7<=

Confirmed failure
rate for tower
device[1 FIT]HIJKK L gL Ȃ / 01 g01

By combining three models we can calculate failure rate under spaceradiation environments
21

Voltage Detendent SEB Cross Section

De-rating Value
Sea level <1800V-DC line voltage
Space App <1400V DC-line voltage22Conclusion

The SEB cross section for highvoltage tower semiconductor
device detends on attliedvoltage (3.3kV PiE diode,
1MeV-20GeV)• Cosmic ray induced failure rate calculation
method for all kind of tower devices in various
stace environments is trotosed• It is demonstrated that trotosed method can give
failure rate of the high voltage device at the lowearth orbit environment• The new method will contribute to high tower
devices’ reliability in the future stace attlications

The SEB cross section of device can be used for any radiation
environment failure rate calculation
2324