PROTONIC NONVOLATILE FIELD-EFFECT TRANSISTOR MEMORIES IN SI SIO2/SI STRUCTURES/

A low-voltage, radiation-tolerant, nonvolatile field effect transistor (NVFET) memory involving proton motion in SiO2 is illustrated in both bulk Si and silicon-on-insulator devices. Wt: discuss a mechanism by which the protons are created in the oxide layer by a. forming gas ann eal. At low temperature (T < 250 degrees C), the H+ is largely ''impri soned'' in the buried SiO2 layer; i.e., tile ions are sandwiched betwe en the two encapsulating Si layers. The Si layers can be: either c-Si or poly-Si, thus the: technology is compatible with standard Si proces sing. The protons can be reliably and controllably drifted from one in terface to another without any noticeable degradation in the signal pa st 10(6) cycles. Under an unbiased condition, the net proton density i s not significantly affected by radiation up to at least 100 krad (SiO 2). Last, we compare many of the properties of the NVFET to commercial flash nonvolatile memories.