Insulating gate thin film transistor having a thin insulating layer overlapping a thick insulating layer

Claim 1

A THIN FILM TRANSISTOR COMPRISING: (A) A BODY OF SEMICONDUCTOR MATERIAL $.5U THICK DISPOSED ON AN INSULATING SUBSTRATE, (B) OPPOSITELY DISPOSED SOURCE AND DRAIN ELECTRODES DISPOSED ON SAID SEMICONDUCTOR MATERIAL, SAID ELECTRODES SPACED FROM ONE ANOTHER BY AN AMOUNT <10U WITH OPPOSITE ENDS OF THE SOURCE AND DRAIN ELECTRODES SECURED TO ATTACHMENT PADS FOR CONNECTION TO A UTILIZATION DEVICE, (C) A RELATIVELY THICK $9000 A. INSULATING LAYER DISPOSED OVER SAID SOURCE AND DRAIN ELECTRODES EFFECTIVE TO SPACE SAID INSULATOR IN REGISTRATION WITH SAID SOURCE AND DRAIN ELECTRODES, (D) A RELATIVELY THIN $1000 A. INSULATING LAYER COVERING A PORTION OF SAID THICK INSULATING LAYER AND A PORTION OF SAID SOURCE AND DRAIN AND WITHIN THE SPACE THEREBETWEEN, AND (E) A GATE ELECTRODE DISPOSED ON SAID THIN INSULATING LAYER SO THAT SAID GATE ELECTRODE FOLLOWS THE CONTOUR OUTLINE OF SAID INSULATING LAYER AND LIES ALMOST TOTALLY WITHIN THE SPACE BETWEEN SAID SOURCE AND DRAIN ELECTRODES WITH RELATIVELY LITTLE OVERLAP ON EITHER SIDE THEREOF.