IEC 62951-2-2019 pdf free.Semiconductor devices – Flexible and stretchable semiconductor devices -Part 2: Evaluation method for electron mobility, sub-threshold swing, and threshold voltage of flexible devices.
This part of IEC 62951 specifies terms,definitions,symbols,configurations and evaluationmethods that can be used to evaluate and determine the performance characteristics offlexible thin-film transistor (TFT) devices. This document specifies test methods andcharacteristic parameters for accurately evaluating the performance and reliability in practicaluse of flexible TFT devices under the bending status.
IEC 62951-2 There are no normative references in this document.
3Terms and definitions
For the purposes of this document, the following terms and definitions apply.
IS0 and lEC maintain terminological databases for use in standardization at the followingaddresses:
IEC Electropedia: available at
ISO Online browsing platform: available at
3.1 flexible thin-film transistorflexible TFT thin-film transistor fabricated on mechanically flexible substrates such as polymers and metalfoils.
3.2 mobility <of an electron> quantity equal to the quotient of the modulus of the mean velocity of acharge carrier (electron) in the direction of an electric field by the modulus of the field strength [SOURCE: IEC 60050-521:2002,521-02-58,modified — “electron” has been added.J]
3.3 sub-threshold swing parameter for quantifying how sharply the transistor is turned off by the gate voltage, definedby the following formula.
3.4 threshold voltage gate-source voltage at which the magnitude of the drain current reaches a specified low value [soURCE: IEC 60050-521:2002,521-07-24]
3.5 gate voltage Vcs voltage between gate and source
3.6 drain voltage VDs voltage between drain and source
3.7 drain current IDs current between drain and source
3.8 transconductancegm ratio of the increment in the drain current to a corresponding incremental change of thegate-source voltage with the drain-source voltage held constant.
4Test method
4.1 General
To investigate the reliability of the flexible TFTs, bending tests are performed as follows(see Figure 1):
a) prior to any bending, the electrical characteristics of the TFTs are measured;
b)under the mechanical bending state,the electrical characteristics of the TFTs arere-measured as shown in Figure 3.IEC 62951-2 pdf download.