SOI device with reduced drain induced barrier lowering
First Claim
1. A method for semiconductor processing, comprising:
- providing a substrate having a semiconductor layer overlying an insulating layer;
doping desired regions of the insulating layer with electrical dopant, wherein a concentration of the dopant in the desired regions is at least about 1020/cm3 after doping;
forming transistor devices in the semiconductor layer, the transistor devices each having a channel region and a gate region; and
diffusing dopant from the desired regions out into the channel regions of the transistor devices by exposing the substrate to an elevated temperature, wherein a concentration of dopant in the channel regions defines a retrograde dopant profile after diffusing.
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Abstract
A CMOS device formed with a Silicon On Insulator (SOI) technology with reduced Drain Induced Barrier Lowering (DIBL) characteristics and a method for producing the same. The method involves a high energy, high dose implant of boron and phosphorus through the p- and n-wells, into the insulator layer, thereby creating a borophosphosilicate glass (BPSG) structure within the insulation layer underlying the p- and n-wells of the SOI wafer. Backend high temperature processing steps induce diffusion of the boron and phosphorus contained in the BPSG into the p- and n-wells, thereby forming a retrograde dopant profile in the wells. The retrograde dopant profile reduces DIBL and also provides recombination centers adjacent the insulator layer and the active layer to thereby reduce floating body effects for the CMOS device.
26 Citations
24 Claims
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1. A method for semiconductor processing, comprising:
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providing a substrate having a semiconductor layer overlying an insulating layer;
doping desired regions of the insulating layer with electrical dopant, wherein a concentration of the dopant in the desired regions is at least about 1020/cm3 after doping;
forming transistor devices in the semiconductor layer, the transistor devices each having a channel region and a gate region; and
diffusing dopant from the desired regions out into the channel regions of the transistor devices by exposing the substrate to an elevated temperature, wherein a concentration of dopant in the channel regions defines a retrograde dopant profile after diffusing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for forming transistor devices, comprising:
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providing a semiconductor wafer having a silicon layer positioned above an insulating layer;
implanting electrical dopants substantially adjacent an interface between the insulating layer and the silicon layer to form dopant diffusion sources in the insulating layer; and
forming transistor devices in the silicon layer, the transistor devices each having channel and gate regions, wherein channel and gate regions of the transistor devices are formed completely above the dopant diffusion sources, wherein retrograde doping profiles in the channel regions are established by diffusion of the dopants out of the diffusion sources and into the channel regions, wherein diffusion is caused by forming transistor devices. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification