AN AMORPHOUS-SILICON LOCAL INTERCONNECTION (ASLI) CMOS WITH SELF-ALIGNED SOURCE DRAIN AND ITS ELECTRICAL CHARACTERISTICS/

A CMOS device which has an extended heavily-doped amorphous silicon so urce/drain layer on the field oxide and an amorphous silicon local int erconnection (ASLI) layer in the self-aligned source/drain region has been studied. The ASLI layer has some important roles of the local int erconnections from the extended source/drain to the bulk source/drain and the path of the dopant diffusion sources to the bulk. The junction depth and the area of the source/drain can be controlled easily by th e ASLI layer thickness. The device in this paper not only has very sma ll area of source/drain junctions, but has very shallow junction depth s than those of the conventional ones. The electrical characteristics of this device are as good as those of the conventional CMOS device, A n operating speed, however, is enhanced significantly compared with th e conventional ones, because the junction capacitance of the source/dr ain is reduced remarkably due to the very small area of source/drain j unctions. For a 71-stage unloaded CMOS ring oscillator, 128 ps/gate ha s been obtained at power supply voltage of 3.3 V. Utilizing this propo sed structure, a buried channel PMOS device for the deep submicron reg ime, known to be difficult to implement, can be fabricated easily.