Browse Prior Art Database

No Device RAM Cell

IP.com Disclosure Number: IPCOM000052125D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Thomas, DR: AUTHOR

Abstract

A random-access memory (RAM) cell is provided with a gated P-N junction that can be made to break down at a very low voltage when a reverse bias is applied to the gate. The breakdown is enhanced by utilizing a thin gate oxide layer and a shallow junction. A forward bias is used for reading, and a reverse bias is used for writing.

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No Device RAM Cell

A random-access memory (RAM) cell is provided with a gated P-N junction that can be made to break down at a very low voltage when a reverse bias is applied to the gate. The breakdown is enhanced by utilizing a thin gate oxide layer and a shallow junction. A forward bias is used for reading, and a reverse bias is used for writing.

A cell 10 is illustrated in Figs. 1 and 2, where Fig. 1 is a sectional view and Fig. 2 is a plan view, with the sectional view of Fig. 1 being taken through line 1-1 of Fig. 2. A segment 12 of P type silicon having a shallow N/+/ diffusion region is formed within an insulating substrate 14. A word line W/L, made of metal or polysilicon, is disposed over silicon segment 12 adjacent to the N/+/ diffusion region and separated from silicon segment 12 by a thin insulating layer 16, preferably made of silicon dioxide having a thickness of about 100 to 200 angstroms. A bit line B/L, made of metal or a second layer of polysilicon and contacting the Nr region, is formed over and is insulated from word line W/L.

Second and third cells 10A and 10B disposed adjacent to cell 10 and contacted by the bit line B/L are also indicated in Figs. 1 and 2, with cell 10A having silicon segment 12A and cell 10B having silicon segment 12B. Although the cells illustrated in Figs. 1 and 2 are formed in an insulating substrate 14, it should be understood that the cell structure can also be formed in conventional diffused complementary metal-oxide...