Lost Circuits has an interesting interview with Jeff Lewis, VP of Worldwide Marketing at ISi, creators of Z-RAM. Here's an excerpt:

LC: ISi has come up with what might be described as a true breakthrough for memory technology. Can you give us an idea what Z-RAM is all about and why it is such a hot thing right now?

J.L.: Traditional embedded memory technologies are based on a six transistor cell, or even a single transistor, single capacitor structure. As CMOS technology evolves below 100 nm, new memory devices are being considered as DRAM, SRAM and/or Flash replacement. Emerging memory devices include Magnetic RAM (MRAM), Phase Change Memories, nano floating gate memories, single or few electron memories and molecular memories. All these new memory concepts are, however, based on the integration of new and exotic materials in a baseline CMOS process and require a multi device approach (1 transistor plus 1 other device). Introducing such memory concepts implies therefore two breakthroughs: a concept breakthrough and a materials or technology breakthrough.

By harnessing the Floating Body (FB) effect of Silicon On Insulator devices, Innovative Silicon (ISi) has taped out megabit designs for a true capacitor-less, single transistor DRAM - named Z-RAM (Zero Capacitance DRAM) - which is capable of doubling memory density when compared to existing embedded DRAM technology (and achieving five times the density of current embedded SRAM), yet requires no exotic materials, no extra mask steps and no new physics.