Circuit Yield of Organic Integrated Electronics

ASIC Class Presentation By:Mohammad Mottaghi

Based on a paper from ISSCC2003All credits go to the original

contributors.

Motivations for organic elec… Organic TFTs show poor performance

compared to silicon CMOS But organic TFTs also show the potential for

extremely low cost production (printing) Organic TFTs are in a stage of development

as silicon MOSFETs were 30 years ago Organic TFT electronics certainly will not replace CMOS But organic TFT electronics may open new low cost / low

performance (but high volume!) markets

Polymer electronics

Low-end, high volume electronic applications, based on: Mechanical flexibility Low-cost Large area

Potential applications: Electronic barcodes Memories Displays (e-paper)

E-paper

Key feature: solution processing

Materials and technology

Technology

Equivalent Circuit

Operation of the polymer transistor

Operation of the polymer transistor

Mobility of organic semiconductors

Applications of organic ICs

Block diagram of an identification tag

Design of organic identification tags

Design of organic identification tags

Design of organic identification tags

Design of organic identification tags

Characteristics of the code generators

Design of organic identification tags

The 48 bit identification IC

Yield of organic circuits

Measured code generator yield

Outline Introduction:

Applications of organic ICs Design of organic identification tags Yield of organic circuits:

Measurements Analysis Improvement by design

Conclusions

Yield of organic circuits Possible causes of yield loss

Hard faults Less then one vertical short /20mm2

Parameter spread is too large No experimental evidence

Parameter values result in small noise margin for the logic style used

Small parameter variations can make the gate fail

Yield of organic circuits Inverter intrinsic noise margin

Yield of organic circuits Inverter noise margin

Yield of organic circuits

How do transistor parameters influence the noise margin?

Yield of organic circuits

Yield of organic circuits Semiconductor conductivity

Yield of organic circuits Semiconductor mobility

Yield of organic circuits Inverter noise margin: Impact of technology and design parameters

Yield of organic circuits NAND noise margin

Yield of organic circuits NAND noise margin

Outline Introduction:

Applications of organic ICs Design of organic identification tags Yield of organic circuits:

Measurements Analysis Improvement by design

Conclusions

Yield of organic circuits Yield improvement by design Use of a level shifter to move the trip level

Yield of organic circuits Test vehicle: a shift register IC

Yield of organic circuits Test vehicle: a shift register IC

Yield of organic circuits Shift register IC: measurement results

Yield of organic circuits Output of a 32 stage shift register

employing level shifters

Largest organic circuit to date (1888 transistors)

Yield of organic circuits Shift register IC: preliminary yield

results Shift register without level shifter:

functional but still no circuit with more than two working FFs

Shift register with level shifter: 30% yield on the 32 FF circuit

Conclusions The main causes of the low yield have

been understood The new circuit solution shows a

substantially better yield The most complex organic circuit to

date has been measured

Thank you for your attention!

Any question ?