Multifunction Behavior of a Vertical MOSFET With Trench Body Structure and New Erase Mechanism for Use in 1T-DRAM

A multifunctional vertical silicon-on-insulator-based metal-oxide-semiconductor (VSoI-MOS) field-effect transistor with trench body structure was designed. It can act as a high-performance transistor (HPT) or a capacitorless one-transistor dynamic random access memory (1T-DRAM), depending on the drain/source location and its electrical and transient performances. The VSoI-MOS operated in HPT mode exhibits favorable electrical performance with a lower drain-induced barrier lowering and subthreshold swing; the same device when operated in the 1T-DRAM mode exhibits a clear kink effect in its output characteristics, which facilitates the appearance of floating body effect and a significant improvement in the transient characteristics compared with HPT mode. This paper proposes a new erase mechanism for the 1T-DRAM mode. The mechanism is studied in detail by exploiting the self-heating of holes.