(A) three dimensional dynamic RAM cell with polysilicon transistor on a storage capacitor

Abstract

N-channel inversion mode polysilicon MOSFET``s have been designed and fabricated in small grain polycrystalline silicon on oxidized silicon substrate. Polycrystalline silicon films have been deposited by LPCVD (Low Pressure Chemical Vapor Deposition) method. The electrical properties and performance characteristics of the polysilicon MOSFET``s have been measured and discussed. The application of the polysilicon MOSFET``s as the switching transistor for a 3-Dimensional dRAM(dynamic Random Access Memory) cell is examined. The 3-Dimensional dRAM cell has been constructed with a switching transistor fabricated in a small grain polysilicon layer formed on top of the capacitor area. The dRAM cell operations have been examined with sensing circuits which have also been fabricated in a small grain polycrystalline silicon.