High-Mobility-TFTs

Mobility~10cm2V-1s-1Switchingratio106LowTemperatureProcessFullytransparentoptionsInZnOorZnOChannelPlasmaQuestLimitedincollaborationwithCambridgeUniversityhavebeendevelopinghighmobilityalternativestoa-Si:HTFTdevicesbasedonamorphousmetal-oxides.PQL’spat-entedHiTUSdepositionsystemoffersunparalleledcontrolofmaterialpropertiestoenablethereactivedepositionofZnO(µ~0.4cm2V-1s-1)andInZnO(µ~10cm2V-1s-1)channellayers.Thecontrolexhibitedalsopermitsaccuratecontroloftheresistivityofthechannelfrominsulating(ρ=3x1010Ω.cm)toconducting(ρ=3x10-3Ω.cm)enablingthedepositionofchargeinjectionlayersonthesourceanddraincontacts.TheperformanceoftheIZOlayerhasbeentestedon2µmthermalSiO2bytheUniversityofCambridgeanddemonstrateaswitchingratiogreaterthan6ordersofmagnitude.Dielecticinsulatorshavebeendevelopedwithhighdielectricconstants(k=23forHfO2)suit-ableforhighperformancedevices.Hafniumoxide(breakdown10MVcm-1andρ=2.5x1013Ω.cm)andAluminiumNitride(Breakdown3MVcm-1andρ=2.7x1013Ω.cm)havebothbeenstudied.Theopticaltransmissionofallthelayersis90%transmissionenablingtheproductionoffullytransparentdevices.Allthelayersofthedevicehavebeendepositedatplasticcompatibletemperatures(T70°C).+44(0)[e-mail](V)Ids(mA)Vg=10VVg=7.5VVg=5VVg=2.5VVg=0VVg=-2.5V1.E-121.E-111.E-101.E-091.E-081.E-071.E-061.E-051.E-041.E-031.E-02-20-100102030Vg[V]Ids[A]Vd=5Vd=2Vd=0.2TransportCharacteristicsforIndiumZincOxideChannelon2µmSiO2Insulator