Formation of semiconductor device with resistors

摘要

A semiconductor device includes a semiconductor substrate, trench isolations, a sacrificial layer, a first resist protect oxide (RPO) layer, a second RPO layer and a silicide layer. The semiconductor substrate has first portions and second portions which are alternately disposed, and each of the second portions includes a first resist region with a first resistance, a second resist region with a second resistance and a silicide region. The second resistance is greater than the first resistance. The trench isolations are in the first portions. The sacrificial layer is on the first resist region. The first RPO layer is on the sacrificial layer. The first RPO layer together with the sacrificial layer have a first thickness. The second RPO layer is on the second resist region, in which the second RPO layer has a second thickness smaller than the first thickness. The silicide layer is on the silicide region.

主权项

1. A method for fabricating a semiconductor device, the method comprising:
providing a semiconductor substrate with a plurality of first portions, a first resist region and a second resist region, wherein the first resist region is disposed between two adjacent first portions, and the second resist region is disposed between another two adjacent first portions; forming a plurality of trench isolations in the first portions of the semiconductor substrate respectively; forming a first sacrificial layer on the first resist region and a second sacrificial layer on the second resist region; implanting doping ions into the first resist region and the second resist region of the semiconductor substrate, wherein a doping type of the first resist regions is the same as a doping type of the second resist regions; removing the second sacrificial layer from the second resist region to expose the second resist region with the first resist region still covered by the first sacrificial layer; and annealing the semiconductor substrate to homogenize the doping ions in the first resist region and the second resist region, and to diffuse a portion of the doping ions out of the second resist region, thereby having the second resist region with a remaining doping concentration, wherein a resistance of the second resist region is greater than that of the first resist region.