Slide 1

V. Paidi, Z. Griffith, Y. Wei, M. Dahlstrom,

N. Parthasarathy, M. Seo, M. Urteaga,

M. J. W. Rodwell ,Department of Electrical and Computer Engineering,

University of California, Santa Barbara, CA 93106

L. Samoska, A. Fung,Jet Propulsion Labs, Pasadena, CA 91109

Common Base Amplifier with 7- dB gain at 176 GHz in

InP mesa DHBT Technology

Slide 2

Outline

• Motivation.

• Why Common-base?

• Effect of layout parasitics on circuit stability and MSG.

• InP mesa DHBT process.

• Circuit simulations.

• Device Results

• G-band Power amplifier results.

• W-band Power amplifier results.

Slide 3

Motivation and Previous Results

• Applications for electronics in 140-220 GHz frequency band

Wideband communication systems Atmospheric sensing Automotive radar

• Small signal amplifier results

6.3 dB @ 175 GHz single stage amplifier in InP TSHBT technology, Miguel et.al.,12 dB @ 170 GHz three stage CE amplifier in InP TSHBT technology, Miguel et. al., 6-stage amplifier with 20 6 dB from 150-215 GHz, InP HEMT, Weinreb et. al.

• Power amplifier results 14-16 dBm @140-170 GHz with 10 dB gain in InP HEMT technology, Lorene et. al., 12.5 dBm @90 GHz with 8.6 dB gain in TS InP DHBT technology, Yun et. al., 14-16 dBm @65-145 GHz with > 10 dB gain in InP HEMT technology, Lorene et. al.,

Slide 4

Why mesa -InP HBTs for 140- 220 GHz power amplifiers ?

• fmax > 400 GHz, ft > 250 GHz

• High current density > 3 mA/ m2.

• Vbr,ce0 > 6V

• Low thermal resistance.

High power density, high gain in 140-220-GHz frequency range

Slide 5

Why Common Base ?

RL

InputMatchingnetworkVin Vout

OutputLoadlineMatchingnetwork

Common Base Circuit Schematic

0

5

10

15

20

25

30

10 100

MS

G/M

AG

, dB

Frequency, GHz

Common base

Common Collector

Common emitter

U

Common base has the highest MSG/MAG.

Slide 6

Base inductance

• 0.8 m base contact width Leads to base access inductance.

• Lb ~ 3 pH for 0.8 mX12 m HBT.

Longer finger length results in larger base access inductance

emitter

Ground

Emitter access

Interconnect metal

Polyimidebase

0.8m each

Slide 7

Collector emitter overlap Capacitance reduction

base plug

emitter

semi-insulating InP

N+ subcollector

N- collector

base

collector

N+ subcollector

Lb

CceCce

base

interconnect metal

base plug

emitter

semi-insulating InP

N+ subcollector

N- collector

base

collector

N+ subcollector

Lb

base

interconnect metal

Double-sided collector Contact Single-sided collector Contact

Single-sided Collector contact reduces Collector to emitter overlap capacitance

Slide 8

Cce, Lb degrade MSG/MAG

0

5

10

15

20

25

10 100

MS

G/M

AG

Frequency, GHz

Without Cce

, Lb

With Cce

With Cce

, Lb

base plug

emitter

semi-insulating InP

N+ subcollector

N- collector

base

collector

N+ subcollector

Lb

CceCce

base

interconnect metal

Lb reduces MSG in 140-220-GHz frequency range.

Slide 9

Single-sided collector Contact improves MSG

0

5

10

15

20

25

30

10 100

MS

G/M

AG

Frequency, GHz

Single sided collector

Double sided collector

amplifier designs

base plug

emitter

semi-insulating InP

N+ subcollector

N- collector

base

collector

N+ subcollector

Lb

base

interconnect metal

2-3-dB improvement in MSG.

Slide 10

• Both junctions defined by selective wet-etch chemistry

• Low contact resistances

• NiCr thin film resistors s = 40 /

• MIM capacitor, SiN dielectric.

• ADS momentum modeled CPW transmission lines

• Air bridges strap ground planes

Mesa IC Process: overview

SI InP

CollectorBaseE

sub-collector

polymide NiCr metal 1 SiN Air bridge

Slide 11

Single-stage Common Base power amplifier

Circuit Schematic

Objectives: 180 GHz amplifier, Psat~ 20 dBm

Approach: InP mesa-DHBTs

Simulations: ADS S-parameter, harmonic balance and momentum simulations

RLVoutVin

Input matching network Output loadlinematch

Input matching network Output loadlinematch

Slide 12

Output Large-signal Load-line match

Rex

Ccb

C

Rcb

Rb,spread

Rb,gap

Rb,cont

Lb

Cgap

Cccbx(1-F)

Cccbx(F)

CceRc,spread /2

Rc,spread /2

Rc,cont

Base

Emitter

Collector

A

v

Device Model Load-line match

Circuit optimized for output power not gain

(Simulations)

Slide 13

Single-stage Common Base power amplifier

2 x 2 x 0.8 m x 12 m, AE=38 m2

(Simulations)

-10

-5

0

5

10

100 125 150 175 200 225 250

S2

1, S

11,

S2

2 d

B

frequency, GHz

S21

S22

S11

0

5

10

15

20

0

5

10

15

20

0 5 10 15 20

Out

put P

ow

er,

dB

m, G

ain

, dB

PA

E (%

)

Input Power, dBm

Pout

PAE

Gain

5.3 dB at 180 GHz, 3-dB Bandwidth = 45 GHz, Saturated Pout, = 20 dBm

• Frequency of operation =180 GHz

• 3-dB bandwidth = 45 GHz,

• Gain = 5.3 dB at 180 GHz,

• Pout,sat = 20 dBm.

Slide 14

Two-stage Common Base amplifier

RLVoutVin

50 Ohms 50 Ohms

InputMatchingNetwork

OutputLoadlineMatchingNetwork

InputMatchingNetwork

OutputLoadlineMatchingNetwork

at f0

at f0

Veb,bias

Vcb,bias

Circuit Schematic

Objectives: 180 GHz amplifier, Psat~ 20 dBm

Approach: InP mesa-DHBTs

Simulations: S-parameter and harmonic and momentum simulation in ADS

Slide 15

Two-stage Common Base amplifier

-10

-5

0

5

10

15

150 160 170 180 190 200 210 220

S2

1,

S1

1,

S2

2 d

B

frequency, GHz

S21

S11

S22

6 x 0.8m x 12 m, AE=58 m2

0

5

10

15

20

0 2 4 6 8 10 12 14

Outp

ut P

ow

er,

dB

m,

Ga

in,

dB

Input Power, dBm

Pout

Gain

Frequency of operation =180 GHz

3-dB bandwidth = 45 GHz,

Gain = 8.7 dB,

Pout,sat = 19.5 dBm.

(Simulations)

Power simulations at 180 GHz

Slide 16

Device Performance DC characteristics of a 2 X 0.8 m X 12 m Common-base InP HBT

0

10

20

30

40

50

-2 0 2 4 6 8

I c, mA

VCB

, V

Safe operatingarea

0

0.1

0.2

0.3

0.4

0.5

0.6

-2 0 2 4 6 8

I c, m

A

VCB

, V

0

5

10

15

20

25

30

1 10 100

U, h 2

1 dB

Frequency, GHz

U

h21

f=240 GHz

fmax

=290 GHz

RF characteristics of a 1 X 0.8 m X 8 m HBT biased at Jc= 3 mA/m2, Vce =1.7 V

• Vbr = 7 V.

• ft = 240 GHz, fmax = 290 GHz.

• Relatively lower fmax –• larger base mesas • relatively poorer base ohmics.

Slide 17

Power measurement setup 170-180 GHz

Power meter

Frequencydoubler

W-band PA

DUT

BWOPowerSource

Variableattenuator

W-bandPoweramplifier

W-bandPowermeter

SchottkyDoubler

WR-5Picoprobe

Calorimeter

Probe loss 170-180 GHz band ~ 2.6 dBWR-5Picoprobe

DUT

Slide 18

Power measurement setup 150 GHz

150 GHzGunnPowerSource Variable

attenuator

WR-5Wafer Probe

Calorimeter

Probe loss 150 GHz band ~ 3.0 dB

WR-5Wafer Probe

DUT

Gunn Oscillator

Var Attn

DUT

Calorimeter

Slide 19

176 GHz single-stage Power amplifier

2 x 0.8m x 12 m, AE=20 m2

7- dB gain at 176 GHz.

3-dB bandwidth = 23 GHz.

Pout = 8.7 dBm with 5 dB associated power gain at 172 GHz.

-10

-5

0

5

10

140 150 160 170 180 190 200

S2

1, S

11,

S2

2, dB

frequency, GHz

S21

S22

S11

-10

-5

0

5

10

0

2

4

6

8

-15 -10 -5 0 5

Gai

n,

dB O

utp

ut P

ower

, dB

m

PA

E (%

)

Input Power, dBm

Gain

Output Power

PAE

Bias conditions Ic = 30 mA, Vcb= 1 V Power measurements at 172 GHzBias conditions Ic = 40 mA, Vcb= 2 V

Slide 20

176 GHz single-stage Power amplifier

At 172 GHz 7.53 mW output power with 5 dB associated gain.

Maximum power measured = 8.37 mW at 176 GHz

0

2

4

6

8

10

170 171 172 173 174 175 176 177

Max

imum

Out

put

Pow

er,

dBm

Frequency, GHz

Associated power gain

Maximum output power

Slide 21

176 GHz two-stage Power amplifier

4 x 0.8m x 12 m, AE=38 m2

7- dB gain at 176 GHz.

Pout = 8.1 dBm with 6.3 dB associated power gain at 176 GHz.

Saturated Pout = 9.1 dBm

Ist stage Ic = 25 mA, Vcb= 1 VIInd stage Ic = 30 mA, Vcb= 1 V

0

2

4

6

8

10

0

1

2

3

4

5

-6 -4 -2 0 2 4 6 8 10

Gai

n, d

B, O

utpu

t Pow

er ,

dBm

PA

E (%

)

Input Power, dBm

PAEGain

Output Power

-10

-5

0

5

10

15

140 150 160 170 180 190 200

S2

1,

S1

1,

S2

2 d

B

Frequency, GHz

S21

S11

S22

Power measurements at 176 GHzIst stage Ic = 40 mA, Vcb= 2 VIInd stage Ic = 51 mA, Vcb= 1.8 V

Slide 22

176 GHz two-stage Power amplifier

At 150.2 GHz 10.3 dBm Pout with 3.4 dB associated gain.

-5

0

5

10

15

0

2

4

6

-10 -5 0 5 10

Gai

n, d

B,

Out

put

Pow

er, d

Bm

PA

E (%

)

Input Power, dBm

Gain Output Power

PAE

Slide 23

84 GHz single-stage Power amplifier

4 x 0.8m x 12 m, AE=38 m2

6.5- dB gain at 84 GHz.

Pout = 32.4 mW with 4 dB associated power gain at 84 GHz.

Bias conditions Ic = 37 mA, Vcb= 1 V Power measurements at 84 GHzBias conditions Ic = 56 mA, Vcb= 2.2 V

-10

-5

0

5

10

75 80 85 90 95 100 105 110

S21

, S

11,

S22

, dB

Frequency, GHz

S21

S22

S11

4

6

8

10

12

14

16

0

5

10

15

20

0 2 4 6 8 10 12

Gai

n, d

B,

Out

put

Pow

er, d

Bm

PA

E (%

)

Input Power, dBm

Pout

PAE

Gain

Slide 24

Design and fabrication of W-band (75-110-GHz) G – band (140-220-GHz) power amplifiers in InP mesa DHBT technology

7-dB at 176 GHz with a single-stage common-base amplifier.

Obtained 8.77dBm output power with 5-dB associated power gain at 172 GHz.

Obtained 32 mW at 84 GHz.

Accomplishments

This work was supported by the ONR , JPL , DARPA (USA).