Deep-Implant 1-μm MOSFET Structure with Improved Threshold Control for VLSI Circuitry

MOSFET structures with an optimized doping profile show improved threshold control and subthreshold performance. This is achieved by a low-dose shallow implant defining the level of the threshold and a higher dose deep implant improving short-channel effects like SDIBL and VDIBL. Besides surface and volume barrier lowering, body effect, parasitic capacitance, avalanche multiplication, and breakdown voltage have been investigated. In spite of the increased substrate sensitivity and junction capacitances, the deep-implant concept only provides transistors with reasonable terminal characteristics in the 1-_mum and sub-micrometer range.