John Borland

Comparison of B, BF2 & B18H22 for Extension and BF2, B18H22 & In HALO Implantation for 32 nm Node Using Various Diffusion‐less Annealing Techniques

We compared various p‐type dopant species for source drain extension (SDE) and pocket/HALO implantation when using diffusion‐less annealing techniques for ultra‐shallow junctions (USJ) at the 32 nm node. For SDE, 200 eVB, 900u2009eVBF2 and 3.8u2009keVB18H22 with and without 5 keVGe‐PAI were studied and for HALO, 20u2009keVBF2, 45 keVIn and 80u2009keVB18H22. Diffusion‐less Xe‐lamp Flash anneal (FLA), 900u2009°C spike anneal, 700u2009°C SPE anneal and their combinations were examined for junction quality (dopant activation, junction leakage and implant damage annealing recovery) using RsL, photoluminescence (PLi) and thermal‐wave (TW) rapid process optimization metrology techniques. Ge‐PAI improved dopant activation (Rs) for the Flash and SPE anneals but not with spike anneal and BF2 had the highest Rs values due to retained dose limits. Also Ge+BF2 resulted in junction leakage degradation but the 900u2009°C spike anneal resulted in stable defects and complete implant damage recovery. For HALO, the dopant activation is dose limited fo...

P, Sb and Sn ion implantation with laser melt-LPC (liquid phase crystallization) for high activation n+ ultra shallow junction in Ge epilayer and surface strain-Ge formation for mobility enhancement

Ultra-shallow n+ ion implanted junctions with high dopant activation in high mobility thin Ge epilayer was realized by rapid and controlled Ge melt depth using 308nm Excimer laser annealing. Extremely high Sb activation of 1E21/cm3 for 10nm USJ is > 3x higher than best P activation level of 3E20/cm3 for a 10nm USJ. High level of surface Sb also induced surface tensile strain-Ge which degraded electron mobility while Sn induced surface compressive strain-Ge improving Sb electron mobility by 2x but degraded P electron mobility by 3x. Differential Hall layer mobility depth plots shows Sn implant improved the mobility uniformity in the top 30nm surface. Controlled Ge melt depth can be extended to 7nm n+ USJ using sub-keV ultra-low energy implantation and results will be shown in the future with n+ activation of 1E21/cm3.

High mobility Ge-channel formation by localized/selective liquid phase epitaxy (LPE) using Ge+B plasma ion implantation and laser melt annealing

Localized Ge and SiGe high mobility channel material is needed for 10nm node and beyond CMOS technology. Thin direct >50% SiGe selective epi followed by oxidation for Ge condensation, 100% Ge selective epi or thermal mixing are methods that require a hard mask and epi interface defects with rough surfaces are always an issue. An alternative approach to epi is using photoresist masking as proposed by Borland et al [1] with Ge-infusion doping (dose controlled deposition), a very high dose implantation technique that leads to amorphous deposition followed by low temperature SPE of the amorphous Ge surface layer but residual interface defects remained.

22 nm Node p+ USJ Formation Using PAI & HALO Implantation With Laser Annealing

Boron 200 eV p+ USJ dopant activation and junction leakage was studied with various combinations of PAI (Ge, B36, In & Xe) and HALO (As & Sb) implantation using msec laser annealing between 1220u2009°C and 1350u2009°C. For B only case without PAI or HALO, increasing laser anneal temperature from 1220u2009°C to 1350u2009°C improved dopant activation boron solid solubility (Bss) from 3E19/cm3 to 1.2E20/cm3 with excellent junction leakage below the lower detection limit of 10x due to residual implant damage (EOR defects) beyond the junction. Higher laser anneal temperatures up to 1350u2009°C improved junction leakage to below detection limit and Bss improved to 1.4E20/cm3. With deep Xe‐PAI junction leakage was severely degraded by 5 orders of magnitude to above the upper detection limit of >2.5E‐2A/cm2 but with annealing temperatures >1300u2009°C junction leakage improved, at 1350u2009°C junction leakage improved to 8...

22nm node p+ USJ defect analysis with various PAI and HALO structures using laser annealing

Boron 200eV 1E15/cm2 p+ Ultra Shallow Junctions with various PAI (Ge, Xe & In) and HALO (As & Sb) implantation activated by msec laser annealing (1220°C to 1350°C) were studied using Junction Photo Voltage (JPV) and Modulated Photo Reflectance (MPR). JPV and MPR provided information about junction quality; dopant activation, junction capacitance, residual implant damage and junction leakage. Highest p+ junction quality and best p+ dopant activation was achieved with laser annealing temperatures >1300°C. The results with Sb-HALO were worse than with As-HALO. For HALO implants junction leakage was controlled by direct band to band tunneling while for no HALO it was controlled by end of range residual PAI defects. The high junction leakage (exceeding E-5 A/cm2) could lead to unreliable Rs and junction capacitance determination.

22nm node p+ junction scaling using B 36 H 44 and laser annealing with or W/O PAI

B<inf>36</inf>H<inf>44</inf> molecular dopants were implanted at 100eV and 1E15/cm² B equivalent energy and dose to achieve Xj<7nm and selected wafers also had various PAI (pre-amorphizing implantation) using Ge 10keV, Xe 14keV and In 14keV to create an amorphous layer 16–17nm deep. All the wafers were MSA (msec annealed) by DSA laser at 1175°C, 1225°C, 1275°C and 1325°C and the results show that the Rs and Bss values for B<inf>36</inf>H<inf>44</inf> without PAI was always better than those reported using monomer B and BF<inf>2</inf> with MSA even though the retained dose was only 67% compared to 100% for monomer B and 55% for BF<inf>2</inf> and we noted that the surface oxide directly affects the retained dose. Adding Ge or In PAI had no effect on dopant activation due to the self-amorphization effects of B<inf>36</inf>H<inf>44</inf> however, Xe-PAI improved activation by 20% but degraded junction leakage. In-PAI also had the highest lifetime. However, we noted that Xe-PAI behaves differently compared to Ge-PAI and In-PAI, TW values were always much higher and independent of the anneal technique (MSA, spike/RTA or furnace anneal) even though no defects could be detected by X-TEM suggesting uniform distribution of vacancy cluster defects throughout the amorphous region.

Cluster Ion Implantation System: Claris for Beyond 45nm Device Fabrication (Ii)

Newly developed sweep beam Cluster ion implanter: CLARIS with 0.2-7keV energy range for Boron beam and 1-10keV energy range for Carbon beam is introduced. Novel Cluster ion implantation technology is capable for 45nm beyond device requiring USJ formation ( 70%) and low sheet resistivity (<1200Ω/sq). Comparison of retain dose and sheet resistivity of B18, BF2, and B beams with FLA shows the superiority of the B18 implantation for less than 500eV implantation.

New metrologies for annealing of USJs and thin films

New metrologies for process characterization of annealing for dopant activation in CMOS transistors now include 4-point probes with probe spacing on the micron scale as well as non-contact methods using optical excitation of carriers for measurements of sheet resistance, leakage currents and various indications of the effects of carrier recombination at residual defects. In addition, optical methods have been extended to characterize the effects of annealing and film growth on local strain as measured by bow, site flatness and Raman spectroscopy. These new metrologies allow characterization of anneal process variations across whole wafers to the sub-mm scale and beyond for Rapid Process Optimization.

22nm node n+ SiC stressor using deep PAI+C 7 H 7 +P 4 with laser annealing

We investigated n+SiCP stressors formation by C & P implantation with various amorphization techniques and using high temperature laser annealing SPE technique. Both monomer C and molecular C (C<inf>7</inf>H<inf>7</inf>) with P<inf>4</inf> implant doping was compared as well as with pre-amorphizing implants (PAI) using Ge, Xe or Sb to enhance the Csub level through SPE amorphous layer regrowth. A P dopant activation level of 4E20/cm³ and a Csub level of 1.52% for Sb-PAI+C<inf>7</inf>+P<inf>4</inf> was realized with s strain layer depth of 50nm using a 1325°C peak laser anneal temperature.

Solid solubility limited dopant activation of group III dopants (B, Ga & In) in Ge targeting sub-7nm node low p+ contact resistance

Low contact resistance (Rc) is key to boost device performance for sub-10nm node. At VLSI Technology Symposium 2016 Samsung reported they reduced Rc by 10% from 14nm to 10nm bulk FinFET technology [1]. TSMC in their beyond 10nm node FinFET paper reported reducing S/D (source/drain) parasitic resistance and enhanced contact process [2] and at IEDM-2016 reported 7nm FinFET reduced S/D parasitic resistance and developed a novel contact process [3]. A complete session #7 was dedicated to “Contact Resistance Innovations for Sub 10nm Scaling” with 4 papers at the VLSI Technology Symposium 2016 [4-7]. To achieve Rc in the low E-9 Ωcm² requires active dopant carrier concentration >5E20/cm³ to low E21/cm³. For SiP n+ S/D contacts P >1E21/cm³ active dopant carrier concentration is realized with laser melt annealing resulting in Rc <1E-9 Ωcm² [6]. For 70%-SiGe p+ S/D contacts IMEC reported using pre and post Ge amorphous implants to boost the B-implant activation with nsec laser melt annealing to reduce Rc from 1.2E-8 Ωcm² to 2.1E-9 Ωcm² [4]. IBM/GF on the other hand reported reducing SiGe p+ S/D Rc from 1.3E-8 Ωcm² to 1.9E-9 Ωcm² by using a thin 12nm 100%-Ge trench-epi and switching from a p+ Ge:B to a p+ Ge:B:group-III metastable alloy for surface interface doping [8]. The group-III Me-alloy in Ge boosted p+ dopant activation from ∼1E19/cm³ with B to ∼8E20/cm³ with Ge+Me-alloy. They mentioned no difference between msec non-melt and nsec melt laser annealing.