Fabrication and characterization of gridded MANOS capacitors for quick investigation of various gate stack configurations

The demand for high-capacity, low-power memory is increasing rapidly as modern portable electronic devices boost performance while decreasing in size. Due to its many advantages over traditional floating gate memory, SONOS-type nonvolatile semiconductor memories and their various derivatives seem to be the next step in the evolution of NVSM technology. The rise of this memory technology requires a quick turnaround in the fabrication of the devices, as well as quick characterization of the gate stack.;We have fabricated gridded MANOS capacitors in the Sherman Fairchild Laboratory. The gridded capacitor structure allows one to quickly fabricate and characterize new and exotic gate stacks for use in charge trapping NVSM. This technique does not require ohmic contacts to the N+ regions, provides for fast turn-around evaluation of gate stacks, can also be employed for mobility extraction, and can be eventually employed in cluster tool operation.;Metal-Aluminum Oxide-Nitride-Oxide-Silicon (MANOS) and Metal-Aluminum Oxide-Hafnium Oxide-Nitride-Oxide-Silicon (MAHNOS) NVSM capacitors have been fabricated on <100> p-type silicon wafers with a resistivity of 20 O-cm. A grid structure with line widths of 5um and line spacing, ranging from 30um to 300um, is defined and doped with phosphorous.;The gate stack consists of a high quality 2.1nm SiO2 tunnel oxide layer thermally grown in a triple-wall oxidation furnace, a 7.7nm silicon-rich nitride deposited by LPCVD, and two sets of blocking oxides deposited by atomic layer deposition. The first set of devices has an Al2O3 blocking oxide, while the second set has an Al2O3-HfO 2 7:3 ratio mix.;Various fundamental and dynamic electrical characterization techniques such as C-V, LVR, and speed write/erase, are described and performed on the wafer sets to determine the effect of the gridded structure, as well as the effect of the high-k dielectric blocking oxide. An automated flatband voltage tracking system has also been developed to aid in the characterization of NVSM capacitors.