SOLID-II: High-voltage high-gain kilo-Ångstrom-channel-length CMOSFET´s using Silicide with self-aligned ultrashallow (3S) junction

A simple novel pile-up phenomenon which leads to an available layered structure of silicide with self-aligned ultrashallow (3S) junction is described. Heavily piled-up impurity (P or B) layers less than 50 nm deep under refractory metal (Ti, W, or Pd) silicide accomplish excellent p-n junction characteristics. Good ohmic properties are also obtained with contact resistivity less than 4 × 10^-6ω cm²independent of substrate concentration. This notable profile can easily be realized when a high dose (≥ 5 × 10¹⁵cm^-2) of impurity is implanted not through but into the refractory metal without intermixing, and followed by Silicidation. An application of this new phenomenon for a kilo-Ångstrom-channel-length CMOSFET is also proposed and evaluated using two-dimensional numerical simulation. In the advanced device, silicide on lightly doped drain II (SOLID-II), the breakdown voltage and current gain product of kilo-Ångstrom-channel-length MOSFET´s with 3S junction can be significantly improved in comparison with those of conventional LDD devices. In the 0.3-µm-channel-length devices, current gain reduction in SOLID-II is less than 10 percent compared with that in the standard device. However, in the LDD more than a 20-percent reduction is unavoidable with the same breakdown voltage of 8.5 V. It is proved that the SOLID-II: structures can be used very effectively as a 0.2-0.5-µm-channel-length CMOSFET operatable with 5-V power supply.