Research On Reverse Voltage Performance And Thermal Reliability Of Lateral Organic Power Field Effect Transistor

Power semiconductor device is a kind of power electronic component used as power conversion and control.It is widely used in various high voltage and high temperature environment.With the rapid development of semiconductor industry,people’s requirements for power semiconductor devices are constantly updated.In addition to meeting the high voltage and high current working environment,it also needs to be flexible,low cost,large area film forming,environmental friendly and other characteristics to meet the application requirements in other scenarios.However,the traditional inorganic semiconductor materials can not meet the needs gradually because of the shortcomings of complex process,high cost,opacity and so on.Due to its inherent advantages of easy processing,flexibility and transparency,organic semiconductors(OSCs)have been widely used in solar cells,lasers,sensors,wearable devices and other fields.However,in the field of power devices,due to the poor thermal stability and electrical stability,there is a lack of reliable organic power field-effect transistor,so organic power devices based on integrated circuits have not been used in practice.In high temperature and high voltage environment,organic is prone to denaturation,so that the transistor has irreversible damage.Therefore,improving the voltage resistance and thermal stability of organic transistors through structural design is the key to the preparation of organic power devices.This thesis aims at the copolymer organic field-effect transistor(OFET),aiming at the problem that high temperature and high pressure restrict the stability of organic transistor,focusing on transistor structure optimization,we are committed to building a new OFET device structure and analyzing its voltage resistance mechanism.The thermal reliability test was carried out.The research contents include:First,a structure of organic field-effect transistor with lateral drift region(LDR-OFET)is proposed.An innovative lateral drift region is added between the gate and drain.The addition of the drift region structure can significantly improve the reverse voltage performance of the transistor in the off-state,and the voltage resistance is increased by 10 times.Second,the avalanche breakdown characteristics of LDR-OFET devices are studied.By modeling transistors and constructing back-to-back Schottky junction devices,it is proved that the electrical breakdown mechanism of LDR-OFET is not thermoelectric breakdown through repeatable breakdown behavior.It is proved that the breakdown mechanism of the transistor is not Zener breakdown,so the breakdown mechanism of the transistor is avalanch-like breakdown through the test results of the transistor breakdown voltage with positive temperature coefficient at different ambient temperatures.Third,the reliability of LDR-OFET under ambient temperature and self-heating is explored.By measuring the output characteristics,transfer characteristics and breakdown voltage of the transistors at different ambient temperatures,it is proved that the copolymer organic power field effect transistor can work normally in the ambient temperature range of 300K-450 K.In addition,through the cyclic breakdown test of the same transistor,it is proved that the copolymer field effect transistor has good self-thermal stability.