Abstract:
A method of forming a titanium silicide (69) includes the steps of forming a transistor having a source region (58), a drain region (60) and a gate structure (56) and forming a titanium layer (66) over the transistor. A first anneal is performed with a laser anneal at an energy level that causes the titanium layer (66) to react with the gate structure (56) to form a high resistivity titanium silicide phase (68) having substantially small grain sizes. The unreacted portions of the titanium layer (66) are removed and a second anneal is performed, thereby causing the high resistivity titanium silicide phase (68) to convert to a low resistivity titanium silicide phase (69). The small grain sizes obtained by the first anneal allow low resistivity titanium silicide phase (69) to be achieved at device geometries less than about 0.25 micron.
Abstract:
A method of reducing implant dose loss is provided. The method includes performing multiple low dose implant steps with interspersed anneal steps, thereby avoiding amorphous-silicon formation. The anneal steps may be performed at high temperatures or at low temperatures.
Abstract:
Submicron-dimensioned, p-channel MOS transistors and CMOS devices a formed using nitrogen and boron co-implants for forming p-type well regions, each implant having a parabolically-shaped concentration distribution profile. During subsequent thermal annealling, boron-doped wells are formed, each having a retrograde-shaped concentration distribution profile exhibiting a peak boron concentration at a preselected depth below the semiconductor substrate surface. The inventive method reduces “short-channel” effects such as “punch-through” while maintaining high channel mobility.
Abstract:
Short channel effects are curtailed thereby increasing integrated circuit speed by forming a channel dopant with an asymmetric impurity concentration profile. Embodiments include ion implanting Si or Ge at a large tilt angle to amorphize a portion of a designated channel region with a varying degree of amorphization decreasing from the intended drain region to the intended source region, substantially vertically ion implanting channel dopant impurities and annealing. During annealing, diffusion is retarded in areas of increased amorphization, thereby forming an asymmetric impurity concentration gradient across the channel region increasing in the direction of the source region.
Abstract:
Transient enhanced diffusion (TED) of ion implanted dopant impurities within a silicon semiconductor substrate is eliminated or substantially reduced by displacing “knocked-on” oxygen atoms from an overlying oxygen-containing layer into the substrate by ion implantation. The “knocked-on” oxygen atoms getter silicon interstitial atoms generated within the substrate by dopant implantation, which are responsible for TED.
Abstract:
A method of performing tilted implantation for pocket, halo and source/drain extensions in ULSI dense structures. The method overcomes the process limit, due to shadowing effects, in dense structures, of using large angle tilted implant techniques in ULSI circuits. A gate opening in an oxide layer is defined and partially filled by insertion of nitride spacers to define an actual gate window opening. The small angle tilted implant technique has the equivalent doping effect of large angle tilted implants, and circumvents the maximum angle limit (&thgr;MAX) that occurs in the large angle implant method. The small angle tilted implant technique also automatically provides self alignment of the pocket/halo/extension implant to the gate of the device.
Abstract:
In one embodiment, the present invention relates to a method of removing fluorine from a gate conductor involving the steps of providing a semiconductor device containing a substrate, a gate insulator layer overlying a portion of the substrate, a gate conductor containing fluorine overlying the gate insulator layer, and a source and a drain region adjacent the gate insulator layer; and laser annealing the semiconductor device at an energy level sufficient to melt at least a portion of the gate conductor thereby inducing the removal of fluorine from the gate conductor. In another embodiment, the present invention relates to a method of making a transistor involving the steps of forming a gate conductor overlying a gate insulator layer, wherein the gate conductor and the gate insulator layer overlie a portion of a substrate, doping the substrate and gate conductor with BF.sub.2.sup.+ to form in the substrate a source region and a drain region adjacent the gate insulator layer and a channel region between the source and drain regions and under the gate insulator layer; laser annealing the doped gate conductor, the doped source region and the doped drain region at an energy level sufficient to melt at least a portion of the doped gate conductor, thereby removing fluorine from the melted portion of the gate conductor; and subsequently performing an RTA to activate the doped source region and the doped drain region
Abstract:
Lightly doped regions are implanted into an amorphous region in the semiconductor substrate to significantly reduce transient enhanced diffusion upon subsequent activation annealing. A sub-surface non-amorphous region is also formed before activation annealing to substantially eliminate end-of-range defects on crystallization of amorphous region containing the lightly doped implants.
Abstract:
A method of forming a transistor includes the steps of forming a gate structure (56) overlying a gate oxide layer (54), wherein the gate structure (56) and gate oxide layer (54) overlie a substrate (50), thereby separating the substrate (50) into a first region (90) and a second region (92) with a channel region therebetween. The method also includes doping the gate structure (56), the first region (90) and the second region (92) and annealing the doped gate structure (56) with a laser anneal, thereby driving the dopant through a substantial depth of the gate structure (56). Lastly, a source region (94) and a drain region (96) are formed in the first region (90) and the second region (92), respectively, wherein the dopant is further driven into the gate structure (56). Consequently, the dopant is driven substantially deeper in the gate structure (56) than in the shallow source region (94) and drain region (96) junctions to allow decoupling of poly depletion from the need for shallow junctions.
Abstract:
A method of forming an oxide enhancing region, such as phosphorus, in a semiconductor substrate with minimal damage is provided. The method includes the steps of forming an oxide enhancing region in the semiconductor substrate to a depth below the semiconductor substrate. A 308 nm excimer laser is then applied to the oxide enhancing region in order to reduce the damage caused by forming the oxide enhancing region. A uniform and reliable oxide layer is then formed on the surface of the substrate over the damage reduced oxide enhancing region.