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Analysis Analysis ofof Heterojunction Bipolar Heterojunction Bipolar TransistorsTransistors

2

OutlineOutline

3-D Structure of Single Finger and Three Fingers3-D Structure of Single Finger and Three Fingers C-up HBTC-up HBT

A 3-D modal of single finger and three fingers C-up HBT

Adjust the Thickness of PHS Layer and GaAs Substrate

Compare with the results of 2- D modal

The results under the different boundary condition

ConclusionConclusion

3-D Structure of Single Finger C-up HBT3-D Structure of Single Finger C-up HBT

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A 3-D Modal of Single Finger C-up HBTA 3-D Modal of Single Finger C-up HBT

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Temperature distributions in C-up HBT of 3-D Temperature distributions in C-up HBT of 3-D Modal Modal ((1/4 Symmetry1/4 Symmetry))

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Temperature distributions in C-up HBT of 3-D Temperature distributions in C-up HBT of 3-D Modal Shows by Isosurface Modal Shows by Isosurface ((1/2 Symmetry1/2 Symmetry))

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Compare with the Results of 2- D ModalCompare with the Results of 2- D Modal

385

395

405

415

4 5 6 7 8

PHS thickness(um)

Max

. Tem

pera

ture

(K)

1 Finger for 3D Anlysis

1 Finger for 2D Anlysis

382

385

388

391

394

11.5 13.5 15.5 17.5 19.5

Substrate thickness(um)

Max

. T

empe

ratu

re(K

)

1 Finger for 3D Anlysis

1 Finger for 2D Anlysis

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Adjust the Thickness of PHS Layer and GaAs SubstrateAdjust the Thickness of PHS Layer and GaAs Substrate

380

390

400

410

420

11.5 13.5 15.5 17.5 19.5

Thickness of substrate (um)

Max

. tem

pera

ture

in H

BT

s (K

)

2-D PHS = 8um3-D PHS = 8um3-D PHS = 7um3-D PHS = 6um3-D PHS = 5um3-D PHS = 4um2-D PHS = 4um

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3- D Modal Temperature distributions Compare 3- D Modal Temperature distributions Compare with the Results of 2- D Modalwith the Results of 2- D Modal

The Temperature distributions The Temperature distributions of 3- D Modalof 3- D Modal

The Temperature distributions The Temperature distributions of 2- D Modalof 2- D Modal

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3- D Modal Temperature distributions Compare 3- D Modal Temperature distributions Compare with the Results of 2- D Modalwith the Results of 2- D Modal ( (con.con.))

The Temperature The Temperature distributions of 3- D Modaldistributions of 3- D Modal

The Temperature The Temperature distributions of 2- D Modaldistributions of 2- D Modal

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Comparison of temperature distribution in C-up HBT Comparison of temperature distribution in C-up HBT

with a thicker and a thinner thermal viawith a thicker and a thinner thermal via

Original thicker thermal via ：Substrate ＝ 19.5um ； PHS ＝8um

A thinner thermal via ：Substrate ＝ 13.5um ； PHS ＝6um

298.5 398

3-D Structure of Three3-D Structure of Three Finger C-up HBTFinger C-up HBT

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A 3-D Modal of Three Finger C-up HBTA 3-D Modal of Three Finger C-up HBT

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Temperature distributions in C-up HBT of 3-D Temperature distributions in C-up HBT of 3-D Modal by Finger Pitch = 18 um Modal by Finger Pitch = 18 um ((1/4 Symmetry1/4 Symmetry))

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Temperature distributions in C-up HBT of 3-D Temperature distributions in C-up HBT of 3-D Modal by Finger Pitch = 10 um Modal by Finger Pitch = 10 um ((1/4 Symmetry1/4 Symmetry))

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Temperature distributions in C-up HBT of 3-D Temperature distributions in C-up HBT of 3-D Modal Shows by Isosurface Modal Shows by Isosurface ((1/2 Symmetry1/2 Symmetry))

Finger Pitch = 18 umFinger Pitch = 18 um

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Temperature distributions in C-up HBT of 3-D Temperature distributions in C-up HBT of 3-D Modal Shows by Isosurface Modal Shows by Isosurface ((1/2 Symmetry1/2 Symmetry))

Finger Pitch = 10 umFinger Pitch = 10 um

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3- D Modal Temperature distributions Compare 3- D Modal Temperature distributions Compare with the Results of 2- D Modal with the Results of 2- D Modal ((Finger Pitch = 18 um Finger Pitch = 18 um ))

The Temperature The Temperature distributions of 3- D distributions of 3- D ModalModal

The Temperature The Temperature distributions of 2- D distributions of 2- D ModalModal

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3- D Modal Temperature distributions Compare 3- D Modal Temperature distributions Compare with the Results of 2- D Modalwith the Results of 2- D Modal ( (con.con.))

The Temperature The Temperature distributions of 3- D distributions of 3- D ModalModal

The Temperature The Temperature distributions of 2- D Modaldistributions of 2- D Modal

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Compare with the Results of 2- D ModalCompare with the Results of 2- D Modal

420

430

440

450

460

470

480

490

500

510

4 5 6 7 8

PHS thickness(um)

Max

. Tem

pera

ture

(K)

Pitch = 18 um for 3D AnlysisPitch = 18 um for 2D AnlysisPitch = 10 um for 3D AnlysisPitch = 10 um for 2D Anlysis

405

420

435

450

465

11.5 13.5 15.5 17.5 19.5Substrate thickness(um)

Max

. Tem

pera

ture

(K)

Pitch = 18 um for 3D AnlysisPitch = 18 um for 2D AnlysisPitch = 10 um for 3D AnlysisPitch = 10 um for 2D Anlysis

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ConclusionConclusion

The relation of maximum temperature to substrate thickness

is linear, and the relation of maximum temperature to PHS

thickness is a cubic equation in 2D and 3D analysis.

The temperature distribution of 3D modal is similar to 2D

modal, but the result of 2D modal is higher than that of 3D

modal.

The 3D analysis of 1-finger C-up HBT shows that the

thickness of thermal via can be reduced 32% to provide the

same thermal performance.