SHALLOW JUNCTION FORMATION BY PHOSPHORUS DIFFUSION FROM IN-SITU SPIKE-DOPED CHEMICAL-VAPOR-DEPOSITED AMORPHOUS-SILICON

Shallow and lateral homogeneous delineated n+p-junctions were formed b y utilizing solid source diffusion from a deposited amorphous silicon layer with an in situ imbedded P rich zone. After heat treatment the l ayer remains flat, surface roughness has found to be less than 3 nm. D opant pile up at the Si-layer/Si-substrate interface has been observed and interpreted based on segregation phenomena. From the time depende nce the P segregation pile up has found to be diffusion limited except of a small starting period. The dopant concentration in the Si-substr ate drops down over more than 2 orders of magnitude in a thickness ran ge less than 20 nm.