Wide Band Gap Semiconductor Devices for Rational Use of ...€¦ · Rational Use of Energy. RUE....

Consolider RUE (CSD2009-00046)

Wide Band Gap Semiconductor Devices for

Rational Use of EnergyRUE

José MillánCNM

http://www.uniovi.es/

http://www.robotiker.com/


Outline

• Why WBG Semiconductors?• The CONSOLIDER RUE at a glance• The RUE Consortium• The RUE WPs• Results• Future Trends of WBG Power Devices




“efficient processing of electrical energy through means of electronic switching devices ”

Power Electronics is:

40% of Energy consumed as electricity




Power Electronics: Electrical Energy Processing




Electrical Energy Areas

• Energy generation (1)

• Energy transmission &distribution (2,3)

• Energy storage (4)

• Energy usage & conversion (5,6)




• Increased power densities• Lower electromagnetic emissions• Plug-and-go systems• Extreme operating environments• Higher levels of integration• Lower cost

Moore’s Law for Power Devices:

Doubling frequency and power density every 4.5 years




• Si devices are limited to operation at junction temperatures lower than 200 ºC.

• Si power devices not suitable at very high frequencies.

• SiC and GaN offer the potential to overcome both the temperature, frequency and power management limitations of Si.

Why WBG Semiconductors?




• SiC&GaN process technologies are more “mature”.

• At present, SiC shows the best trade-off between properties and commercial maturity.

• GaN can offer better HF and HV performances, but lacks of high quality large substrates (no vertical devices).

• GaN lower thermal conductivity than SiC.

• GaN: 2DEG heterojunctions (InAlGaN alloys) grown on SiC or Si substrates.

• Currently, it is a sort of competition SiC vs GaN, in a battle of performance versus cost.

• No clear winner at the moment. They will find their respective application niches with a tremendous potential market.

Why WBG Semiconductors?




Physical Properties of Semiconductors for Power Devices

Material Eg (eV)@300K

µn(cm²/Vs)

µp(cm²/Vs)

Vsat(cm/s)

Ec(MV/cm )

λ(W/cm.ºK)

εr

Si 1.12 1450 450 1 × 107 0.25 1.5 11.7

4H - SiC 3.2 950 115 2 × 107 2.2 5 10

GaN 3.39 1000 350 2.2 × 107 3 1.3 8.9

Diamond 5.6 2200 1800 2.7 × 107 10 22 5.7




WBG-based Devices

• Wider Energy Bandgap lower leakage currents and high operating temperatures. Radiation hardness is also improved.

• Higher critical electric field thinner blocking layers and higher doping concentrations lower on-resistance. Unipolar HV devices feasible.

• Higher electron saturation velocity Higher operating frequencies.

• Higher thermal conductivity better power dissipation (improves heat spreading) - possibility of working at higher current densities – higher operating temperatures.

---------------

• 2 kV SiC Schottky diode with similar losses than a 150 V Si Schottky diode




Consolider RUE at a glance

• Main objective: to develop power WBG semiconductor devices aimed at• an important improvement in the performance of existing

power converters, and • the development of new power converters • In both cases seeking a more Rational Use of the electric

Energy

• SiC and GaN are the best options due to:• theoretical properties (HV capability, HT operation and HSS)• real commercial availability of the starting material (wafers)• maturity of their technological processes





• The development of this generation of power devices includes:• the study, design and fabrication of new power devices• design and implementation of novel packages according to the

voltage, temperature and frequency ranges of these devices. • new characterization and simulation tools • the investigation of the suitable circuitry: new drivers,

controllers, converter topologies, control strategies, etc.

• The project would not be completed if the real advantages of the new devices were not tested in real applications !!





> 60 PhDs

5 year duration

Funds: 4.56 M€




The RUE Consortium






The WorkPackages

The Project is split into three workpackages:

• WP1 deals with the development of SiC and GaN devices.

• WP2 develops the interface technologies to use these devices in real systems.

• WP3 includes several proofs of concepts concerning new and innovative niches for HT and HV capabilities, and HSS operation of WBG power devices.



Consolider RUE (CSD2009-00046) ApplicationsWork Package 3




Summary Diagram




Critical Packaging Elements• Hermetically sealed package• Die attach• Die bonding

Optimized for high temperature operation and -170°C/+300°C thermal cycling

Results: 300V, 5A SiC Schottky diode for ESA BepiColombo

Mission (solar panel protection)

1,9

1,95

2

2,05

2,1

2,15

2,2

2,25

0,0 100,0 200,0 300,0 400,0 500,0

T ime (hours)

Fo

rwar

d v

olt

age

(V)

Ni Schottky diode withhermetic sealing

W Schottky diode

Forw

ard

volta

ge(V

)

Vf at 5A and 270ºC

Time (hours)1,9

1,95

2

2,05

2,1

2,15

2,2

2,25

0,0 100,0 200,0 300,0 400,0 500,0

T ime (hours)

Fo

rwar

d v

olt

age

(V)

Ni Schottky diode withhermetic sealing

W Schottky diode

Forw

ard

volta

ge(V

)

Vf at 5A and 270ºC

Time (hours)




1.2kV & 3.5kV 25mm2 SiC Schottky Diodes

VAK= 1.78V @ 50A (25mm2 diode)

1.2kV diodes: estimated epilayer resistance, Repi = 1.5 mΩ.cm2

For these diodes’ size starting material is a must.

Starting material from CREE: 3” ultralow micropipes 4H substrate

Wafer ∅ 75 mm




Large area SiC JFET

• ACCUMOS vertical power device• 5mmx5mm transistors• 2 or 3 terminals devices• 7 photolitographic mask levels• 2 µm minimum feature size



Wide Band Gap Semiconductor Devices for Rational Use of ...€¦ · Rational Use of Energy. RUE....

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