Increased Pulse Rep. Rates for Solid State Thyratron ... Power... · Increased Pulse Rep. Rates for...

Increased Pulse Rep. Rates for Solid State Thyratron Replacements

John WaldronSilicon Power Corporation280 Great Valley PkwyMalvern, PA 19355

PPPS 2019 Orlando, FL 23-282 June, [email protected]

mailto:[email protected]


Outline

• Introduction to Solidtron’s Enabling Technology– Pulse discharge targeted designs

• Solidtron Performance– Discharge Performance

– Increased Pulse Repetition Rate Strategy/Results

• Solid State Discharge Switch Replacements – Motivation

– Approach

– Experimental results

• Summary

• Questions

2


160,000 cells/cm2

SGTO

GTO

~ 50 cells /cm2

SGTO Advantages:

Cell structure 3000 x denser

Upper transistor >100x improved

• Forward drop greatly reduced

• Three times lower turn-off switching loss

Die sizes from 3x3mm to 15x22mm in 200mm IC foundry providing very high yield, repeatability and uniformity!

3

Super-GTO Vs. GTOSGTO is an IC foundry-fabricated GTO mated with Silicon Power’s proprietary low inductance ThinPak package

• Turn-on improved by 2 orders of magnitude

PPPS 2019 Orlando, FL 23-282 June, [email protected] 4

Solidtron: The Enabling Technology

Traditional thyristor design revisited, capturing IC house capability• Higher cell density improves current uniformity, drastically improving Τ𝑑𝑖

𝑑𝑡 capability• Upper base doping profile improved for higher gain • Metal interconnects improved, increased upper transistor gain and electrode bonding

area

IC Foundry Solidtron Cell

GTO Versus Solidtron, Fundamental Differences


Solidtron Advantages

• Cell density further enhanced

• Emitter area maximized

• Internal metal interconnect density improved

• Upper transistor gain further improved

• Increased cathode bonding pad area

8 inch starting material and improved manufacturing process further improving yield while driving cost down

5

Solidtron Vs. Super-GTOSolidtron follows SGTO strategy, focusing on pulse discharge versus turn-off applications


1600V Solidtron Product line:• Simple gating schemes (low power, easy isolation)• Unmatched Τ𝑑𝑖

𝑑𝑡 capability (>200kA/ms observed)• Easily implemented in series/parallel configurations

6

Solidtron Performance: Hyper-Fast

Capacitor Voltage (Ch2 Max Ref only)

Anode Current 3kA IPK

160ns ½ period

170ns ½ cycle ring down – Yellow = Anode Current, Cyan = Capacitor Voltage

Turn-on delay <90ns

Jitter <500ps

Fall time <40ns

di/dt >200kA/ms


Solidtron Performance: Hyper-Fast

7

550ns ½ pulse width ring down

1ms ½ pulse width ring down

Solid state discharge switch offers:• Rugged yet simple gate trigger• Repeatable fabrication and performance• Bidirectional current flow capability• Very high MTBF, minimizing down time

Ipk 1.8kA

Ipk 1.1kA

Hyper-Fast 1600V Solidtron Discrete products

Available in:• TO-247 • TO-264• Custom SMT packages


Solidtron: Increased Switching Speed

Punch-through design:• Higher BV for given device thickness• Allows bipolar current conduction• Improves turn-on speed• Reduces commutation time

Lower-base width and doping concentration determines BV


Solidtron: Increased Switching Speed

One factor contributing to commutation time is stored charge remaining in lower-base• Thinner lower-base results in less stored charge • Thinner lower-base reduces distance required for diffused carrier to reach emitter

Physically narrower lower-base is employed

¼

Can be thinned after processing to reduce Ron

Implementing lower voltage devices improves commutation time


Post-Fabrication Speed Enhancement

1

10

100

1000

0 20 40 60 80 100 120

t-o

ff (

us)

Temp °C

Commutation Time vs T at 5kAcm-2

Dose 4

Dose 3

Dose 2

Dose 1

As

fab'd

1

10

100

1000

0 20 40 60 80 100 120

t-o

ff (

us)

Temp °C

Commutation Time vs T at 10kAcm-2

Dose 4

Dose 3

Dose 2

Dose 1

As

fab'd

Reducing Minority Carrier Lifetime:• Increases pulse repetition capability

• Decreases commutation time without the need for complicated gate drive

• Post-fabrication process• Enables 1 design to cover range of applications

• Low-cost, high-volume capable process• Demonstrated an 18x improvement in commutation

time at 110°C and 10kAcm-2

• Favorable tradeoff for Ron and ILeakage

12.5µs → 80kHz


Post-Fabrication Speed Enhancement

1.0E-02

1.0E-01

1.0E+00

1.0E+01

1.0E+02

0 1 2 3 4 5

Lea

kage

Cu

rren

t (µ

A)

Dose #

Leakage Current at 1500V

as fab'd 85°C as fab'd 110°C

1 85°C 2 85°C

1 110°C 2 110°C

3 85°C 3 110°C

4 85°C 4 110°C

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

200 400 600 800 1000 1200

R-o

n (

mO

hm

)

J (Acm-2)

Differential Resistance at 110°C Dose 4 Dose 3

Dose 2 Dose 1

As fab'd

Reducing Minority Carrier Lifetime Tradeoffs:• Lower base gain is reduced, ↑ RON

• Lower τ increases generation current (↑leakage)• However, small ↑RON (<2x) for almost 20x

improvement in pulse rep rate

0 1 2 3 4 5

Rel

ati

ve L

ifet

ime

(A.I

.)

Dose #

Relative Lifetime Vs Dose


Solid State Discharge SwitchesMotivation

• Compliance with RoHS • Eliminate conditioning requirements• Eliminate requisite heaters• Simplify gating

• Built in gating requires TTL/Optical trigger and DC power supply• Improve efficiency

• In both energy transfer and off-state conditions• Improve turn-on delay and jitter• Increase usable lifetime

• No terminal erosion• Eliminate liquid cooling requirements• Increase mechanical installation flexibility• Improved performance over IGBT/SCR-based solid state switch replacements


Hyper-Fast Solid State Thyratron Replacement40kV SSTR-1 (Twin Stack)• Initial TO-247 version demonstrated 365k pulses

o 3kA, 300ns square wave

• Similar 20kV and 60kV derivatives planned to complete the product offering

• Negligible power dissipation in off-state (snubber resistors much higher in value)

• TO-264 version offers up to 30x increase in action

TO-247: SP245-03TO-264: SP275-02


Solid State Thyratron Replacement

40kV SSTR-1 (Twin Stack) Vs. e2v CX2282

Hyper-Fast 1600V Solidtron

• Τ𝑑𝑖𝑑𝑡 capability is >200kA/mSec

• Fiber Optically Triggered

• Small size - 9” Tall, 3.75” Base diameter

• Voltage capability of 40kV

• Yellow - 4.7kA Peak Current w/average Τ𝑑𝑖

𝑑𝑡 of ~60kA/mSec(Circuit Limited)

• Magenta - 36kV Discharge

Anode Current

Capacitor Voltage (Ch2 Max Ref only)

50nSec rise timePeak I >4kARep Rate = 100PPS


Summary

15

• RoHS compliance

• Unparalleled solid state Τ𝑑𝑖𝑑𝑡 capabilities

– Hyper-fast demonstrated 200kA/ms

• 𝑓(𝑖 𝑡 , 𝜏) capability, determined by experimental and/or sim data exceeds most if not all commercially available gas or solid state thyratrons available

• Designed with modular, scalable sub-assemblies

– Enables fitment for most thyratron or ignitron applications

Increased Pulse Rep. Rates for Solid State Thyratron ... Power... · Increased Pulse Rep. Rates for...

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