Liquid Phase Epitaxy (LPE) Formation of Localized High Quality and Mobility Ge & SiGe by High Dose Ge-Implantation with Laser Melt Annealing for 10nm and 7nm Node CMOS Technology
Using high dose Ge implantation >E16/cm2 with photoresist soft mask as proposed in 2004 by Borland et al [1,2]. Localized amorphous Ge surface regions can be formed after Ge-infusion doping by Gas Cluster Ion Beam (GCIB) technique followed by low temperature SPE to form single crystal thin surface Ge epitaxial layers but residual end-of-range (EOR) damage remained. Today, laser melt annealing of implanted junctions are currently being used in production for high quality back-side illuminated CMOS image sensors used in smart phone cameras by several IC and foundry semiconductor manufacturers to completely eliminate any residual implant damage/defects with 100% dopant activation provided the melt depth exceeds the implant damage depth .
Last year at IWJT-2013 Borland et al  reported using Ge-plasma ion implantation at 1E16/cm2 and 1E17/cm2 doses with laser melt annealing to realize up to 55% SiGe by LPE with >4x higher mobility at 160cm2/Vs. One limitation they noted with plasma implantation was poor retained dose due to surface sputtering at low energies which limited the Ge content to <55% for 1E17/cm2 dose. Therefore to overcome this retained dose problem we investigated Ge beamline ion implantation in this paper which should give 100% retained dose.
The Ge surface amorphous layer thickness measured by elipsometry was 15nm while the Ge-SIMS depth profile measures 7nm Ge at 100%. Therma-wave analysis was used to monitor the Ge-implant damage recovery and Ge or SiGe recrystallized epitaxial surface layer after various laser melt annealing conditions of varying power level and pulse duration. The Ge-SIMS depth profiles shows we could vary the melt depth for LPE Ge layer from 10nm to >400nm and the Ge layer content from 97% down to 2% respectively. We will also show X-TEM of the Ge-LPE regions.
Sb implantation was used to investigate n-type dopant activation in Ge at low and high doses of 3E13/cm2 and 3E15/cm2. Rs measurements were done using a special Hx 4 point probe and SRP (spreading resistance profile) depth profiles.
In summary, using high dose beam-line Ge-implantation we realized >7nm amorphous Ge deposition. Epitaxial growth of Ge was achieved by liquid phase epitaxy using shallow laser melt annealing between 10nm and >400nm melt depths.
 J. Borland et al., ECS Oct 2004 meeting, PV 2004-07, p.769.
 J. Borland et al., US Patent #7,259,036 Aug 2007.
 S. Wuu et al., IEDM-2010, paper 14.1.
 J. Borland et al., IWJT-2013 meeting, paper S4-4, page 49.