CAPACITANCE MODULATION FROM SUBMICRON DOMAIN ON FERROELECTRIC-SEMICONDUCTOR MEDIA

Reproduction capacitance signal of a ferroelectric-semiconductor disk memory was studied by numerical simulation under an extremely high-den sity recording condition. Information is recorded by controlling the d irection of the ferroelectric polarization which induces the change of depletion-capacitance of the semiconductor substrate. When the spatia l wavelength is less than 1 mu m, depletion regions connect with each other, which is called the ''punch-through'' effect. It has been consi dered that the depletion-capacitance modulation disappears in the ''pu nch-through'' state. The present numerical simulation, however, sugges ted that for the ferroelectric-semiconductor structure, the modulation signal of depletion-capacitance does not disappear even in the ''punc h-through'' state, because there exist island accumulation regions at the semiconductor surface due to the ferroelectric polarization of dom ains with opposite direction. This result is consistent with previous experimental results. it is suggested that the ferroelectric-semicondu ctor disk memory has a potential for higher density recording than sil icon nitride-silicon disk memories.