Patent ID: 6714435
Filing Date: 2004-03-30
Classification: G11C,H01L

Abstract:
A method for the non-volatile storage of two data bits in a single FET transistor comprising:providing a field effect transistor (FET) having gate, drain, source, and substrate terminals, and having a first ferroelectric region between the gate and the source and second ferroelectric region between the gate and the drain; applying a positive voltage greater than a coercive voltage between the gate and the source to polarize said first ferroelectric region to a first state; applying a negative voltage greater than the coercive voltage between the gate and source to polarize said first ferroelectric region to a second state; applying a positive voltage greater than the coercive voltage between the gate and the drain to polarize said second ferroelectric region to the first state; applying a negative voltage greater than the coercive voltage between the gate and the drain to polarize said second ferroelectric region to the second state; applying a positive voltage less than the coercive voltage on the gate, ground potential on the source, and a positive voltage no greater than the gate voltage on the drain to detect the polarization state of said first ferroelectric region, a high current between source and drain indicating the first state and a low current between source and drain indicating the second state; and applying a positive voltage less than the coercive voltage on the gate, ground potential on the drain, and a positive voltage no greater than the gate voltage on the source to detect the polarization state of said second ferroelectric region, a high current between source and drain indicating the first state and a low current between source and drain indicating the second state.