Polysilicon devices and a method for fabrication thereof

The present invention provides a novel thin film transistor device having the advantages of both conventional thin and thick film devices. The channel region of the device is elevated with respect to the source and drain regions by being made as a thin film while the source and drain regions are relatively thick. Such an arrangement provides high drive current characteristics of a thin film device, whilst mitigating the disadvantageous kink effect in the IV curve and the off-state leakage current known in conventional thin film devices. The invention also provides a fabrication method, and this method may also be employed to manufacture other novel semiconductor devices including EEPROM devices, large double layer storage capacitors and a novel conductivity modulated thin film transistor