Patent ID: 7262992
Filing Date: 2007-08-28
Classification: H04R

Abstract:
1. A hearing aid comprising a data memory that includes a plurality of semiconductor memory cells, wherein each semiconductor memory cell includes: a gate insulating film formed on a semiconductor substrate, on a well region provided in the semiconductor substrate or on a semiconductor film deposited on an insulator; a single gate electrode formed on the gate insulating film; two memory functional units formed on both sidewalls of the single gate electrode; a channel formation region formed under the single gate electrode; and first diffusion regions disposed on both sides of the channel formation region, and the semiconductor memory cell is constituted so as to change an amount of currents flowing from one of the first diffusion regions to the other first diffusion region according to an amount of charges retained in the memory functional unit or a polarization vector when a voltage is applied to the gate electrode, wherein each memory functional unit is made of a first insulator, a second insulator and a third insulator, the first insulator has a function of accumulating charges and, also, has a structure in which the first insulator is sandwiched between the second insulator and the third insulator, the first insulator is made of silicon nitride, and each of the second and third insulators is made of silicon oxide.