Patent ID: 7995380
Filing Date: 2011-08-09
Classification: B82Y,G11C,H01L

Abstract:
1. A method of operating a random access memory (RAM) cell, the method comprising: coupling a pull-up element with a switchable current path between a storage node of the RAM cell and a high voltage source, wherein the pull-up element is a negative differential resistance (NDR) device; maintaining the switchable current path of the pull-up element in an off condition during a first period when the RAM cell is storing a first voltage at the storage node; and turning on the switchable current path of the pull-up element during at least portions of a second period when the RAM cell is storing a second voltage at the storage node, thereby refreshing the second voltage at the storage node, wherein the NDR device is a metal insulator semiconductor field effect transistor (MISFET) that includes a trapping layer for trapping electrons from the switchable current path.