La5Ca9Cu24O41 Layers as 1D Heat Spreaders for

Thermal Management Solutions

Charis Orfanidou

Overview

2

• Thermal Management Problem

& Solution – The Idea

• The La5Ca9Cu24O41 material

• Equations

• Set up problem, Mesh & Results

• Conclusions

R. Viswanath et al., Intel Technology Journal, Q3, 2000

Hot Spot

• Operating System Flux

Spots, Hot Spots

• Operating at high T more possibilities to

failure

Thermal Management Problem

3

Charis Orfanidou 4

Thermal Management Solution – The Idea

The La5Ca9Cu24O41 material

c

b

a

Thermal Conductivity

5

at Room Temperature:

κa = κb ≈ 1 W/m·K

&

κc ≈ 100 W/m·K

La5Ca9Cu24O41 layer c-axis oriented :

Thermally Conducting but electrically insulating

C. Hess et al., Physical Review B, vol.64, 2001

Equations

6

The heat conduction was modeled by solving the steady state, two-dimensional heat conduction equation:

A normal heat flux is applied at the top of the silicon operating elements using Fourier’s law:

Qy = heat flux T = absolute temperature

κx, κy = local values of thermal conductivity

Charis Orfanidou 7

Set up problem

x

y

8

Mesh

• Free Triangular

• 3074 elements

Set up problem

9 Charis Orfanidou

300 K

Silicon (3,4μm)

Operating elements (50nm x 50nm) Si

Heat Flux: 108 W/m2

Silicon Sub (500μm)

1μm

Set up problem

10 Charis Orfanidou

Silicon

Silicon

Silicon

La5Ca9Cu24O41

Set up problem

11 Charis Orfanidou

La5Ca9Cu24O41 (3,4μm)

Silicon Substrate (500μm)

300 K

Hot Spot: 1010 W/m2 heat flux, adjacent operating elements: 108 W/m2

1μm

12 Charis Orfanidou

Silicon

Silicon

Silicon

La5Ca9Cu24O41

Set up problem

Isotherms

13

Silicon La5Ca9Cu24O41

Temperature Profiles

14 Charis Orfanidou

1K

0.5K

Conclusions

• Introducing La5Ca9Cu24O41 layers → “protecting” the adjacent operating elements due to the 1D heat conduction

• Although we are introducing thermal resistance in the device we reduce the T of the adjacent operating elements by almost 1 degree

• Each degree reduction of temperature in the electronic devices can increase their lifetime!

• Simulate layers of the order of nanometers • How much we can approach reality by using

COMSOL Multiphysics

Acknowledgements

16

Prof. Ioannis Giapintzakis Materials Science Group, Mechanical and Manufacturing Engineering Department, UCY

This work was supported by the European Commission through the ITN Marie Curie LOTHERM

Charis Orfanidou

THANK YOU FOR YOUR ATTENTION !!

Charis Orfanidou

Charis Orfanidou 18

Operating Temperature, κLCCO = {1, 100, 1} W/m*K

ΔT = 0.35 K

Charis Orfanidou 19

Operating Temperature, κLCCO = {1, 550, 1} W/m*K

ΔT = 0 K

445

455

465

475

485

495 1

14

9

11

61

11

95

12

99

17

42

18

00

20

16

20

99

24

11

25

23

28

49

30

74

32

20

37

59

39

01

44

91

46

82

53

62

56

13

63

23

65

94

72

50

Tem

pe

ratu

re (

K)

N cells

HS Temp (Si)

HS Temp (LCCO)

1st adjacent (3rd element) Temp (Si)

1st adjacent (3rd element) Temp (LCCO)