Patent ID: 7148570

Claim:
A semiconductor structure comprising: a first semiconductor region characterized by a dopant concentration greater than 1×10 19 /cm 3 ; a second semiconductor region overlying the first semiconductor region, said second semiconductor region comprising silicon and characterized by a dopant concentration less than 1×10 18 /cm 3 and a thickness t1; and a layer comprising titanium directly overlying the second semiconductor region, said layer characterized by a line width no greater than 0.3 μm and a thickness t2, wherein t1>1.2t2; t1/t2 being sufficiently small that, when the layer is reacted with the second semiconductor region to form titanium disilicide, the titanium disilicide is in ohmic contact with the first semiconductor region; t1/t2 being sufficiently large that, when the layer is reacted with the second semiconductor region to form titanium disilicide, the titanium disilicide anneals to a phase with a sheet resistance less than 3 ohms/square.