cjp@megatek.UUCP (Chris Pikus) (04/08/90)
From article <28686@cup.portal.com>, by mmm@cup.portal.com (Mark Robert Thorson): > > Or, will SRAM's eventually surpass DRAM's in density? I've heard this > comparison: how small can you make a capacitor / how small can you make > six transistors. Will transistors eventually become so small that six > interconnected transistors together are smaller than a minimum-size > capacitor. Or will the capacitors scale down as far as transistors > can go? > A physicist freind explained it to me once. He says that in order to make a memory cell, you need capacitance. (Whether in a capa- citor or in the junction capacitance of a transistor.) A laymans interpretation is that capacitive delays are needed in the static memory cell since the stability of the "D flip-flop" (static memory cell) depends on the feedback elements from the output. Granted this minimum capacitance is much smaller than what is in a current capacitor today, but there is a quantum limit. A VLSI expert may want to correct me if I am wrong but I was under the impression that the "capacitor" in a DRAM was merely a degenerate form of a standard VLSI transistor (i.e. using the junction capacitance of the FET as the cap.) Thus, capacitors should scale as far as transistors. -- Regards, Christopher J. Pikus, Megatek Corp. INTERNET: cjp@megatek San Diego, CA UUCP: ...!{uunet hplabs!hp-sdd ames!scubed ucbvax!ucsd}!megatek!cjp
gerry@zds-ux.UUCP (Gerry Gleason) (04/09/90)
In article <345@winston.megatek.uucp> cjp@megatek.UUCP (Chris Pikus) writes: >From article <28686@cup.portal.com>, by mmm@cup.portal.com (Mark Robert Thorson): >> Or, will SRAM's eventually surpass DRAM's in density? I've heard this >> comparison: how small can you make a capacitor / how small can you make >> six transistors. Will transistors eventually become so small that six >> interconnected transistors together are smaller than a minimum-size >> capacitor. Or will the capacitors scale down as far as transistors >> can go? > A physicist freind explained it to me once. He says that in >order to make a memory cell, you need capacitance. (Whether in a capa- >citor or in the junction capacitance of a transistor.) A laymans . . . . Not exactly, you need something that can hold an energy state or value. 20 years ago it was magnetic cores, now it's tiny capacitors. Probably something new and better will come along. Maybe someone knows whether this technology is close to commertial reality, a recent Popular Science had a small write-up on "fero-electric" memory technology. They said the cells could be smaller than DRAM cells, and are non-volitile. If it can be made, I'm sure there are many applications for it. Gerry Gleason