Kyoung Bong Rouh

Multi-wavelength Raman and photoluminescence characterization of implanted n+/p junctions under various rapid thermal annealing conditions

Arsenic (As+) implanted p-type wafers for n+ junction were prepared and annealed in a resistively heated, single wafer rapid thermal furnace in N2. The wafers were non-destructively characterized by multi-wavelength Raman spectroscopy and multi-wavelength photoluminescence (PL) spectroscopy before and after rapid thermal annealing (RTA). Sheet resistance and dopant profiles of n+/p junctions were measured using a four point probe and secondary ion mass spectroscopy (SIMS). Strong correlation among Raman, PL spectra, sheet resistance, dopant profile and RTA conditions were observed. Approximate dopant profiles, crystal quality, junction integrity, dopant activation/deactivation rates, and approximate profiles (location and density) of non-radiative recombination centers of As+ implanted wafers were successfully characterized by multi-wavelength Raman and PL measurements without making contact. Multi-wavelength Raman and PL can provide advantages as in-line, non-contact/non-destructive process and material ...

Novel threshold voltage fine control method for FETs within a wafer using LDSi (Locally Differentiated Scanning ion implant)

The novel threshold fine voltage (hereafter Vt) control method within a wafer was successfully developed. The locally differentiated scanning ion implant (hereafter LDSi) was developed in order to equalize Vt within a whole wafer. The wafer that was done by LDSi method showed very small Vt variation range of 117mV @ thin PMOS short channel (Vt range made by conventional implant without LDSi : 224mV). There was no long channel Vt shift. The portion of high speed DRAMs over 1GHz was increased from 47% to 84% by LDSi without IDD2 fail rate loss. Without decreasing of wafer per hour, we got the dramatic results.