Genshu Fuse

CW Laser Annealing of Polycrystalline Silicon on SiO2 and Effects of Successive Furnace Annealing

CW Ar laser annealing was carried out to reduce the resistivity of polycrystalline silicon implanted with light doses of 1×1012-5×1014B+/cm2. Laser annealing, actually laser melting, and successive furnace annealing effectively reduced the resistivity to almost that of single crystal silicon. TEM, OM and stress observations revealed that the reduction was due primarily to the grain growth of polycrystalline silicon and secondarily to stress relief, from 9×109 dyne/cm2 to 5×109 dyne/cm2, caused by annealing. Grain growth of up to about 3×100 µm and bamboo-joint-like growth were observed.

Blink Furnace Annealing of Ion-Implanted Silicon

A very short annealing of a few seconds duration was carried out by irradiating ion-implanted Si wafers with infra-red radiation emitted from hot Si walls. At low temperatures, the activation of impurities was mostly due to the recrystallization of the amorphous layers and to the annihilation of ion-implanted damage; and at high temperatures to thermal agitation. Full activation was generally realized by blink annealing of 10 s at 1000°C and 1 s at 1100°C without noticeable impurity diffusion. Supersaturation of As was electrically observed.

Formation of ultra shallow p+/n junction in silicon using a combination of low-temperature solid phase epitaxy and non-melt double-pulsed green laser annealing

MOSFETs scaling-down is an effective way to attain high-performance CMOS operating with lower power and leakage current. However, short channel effects have become a serious problem due to the shortening of channel length. One of the promising methods to suppress this problem is by forming a shallow, highly doped and activated source/drain extension region. Fabricating ultra shallow p+/n junction is difficult due to the channeling of boron ions and anomalous boron diffusion during fabrication processes. A combination of Ge pre-amorphization implantation, low-energy boron implantation and two-step annealing, involving low-temperature solid phase epitaxy preannealing followed by non-melt laser annealing was used for forming ultra shallow p+/n junction in silicon. The physical relationship among the regrowth of implanted layer, boron activation and diffusion, and leakage current is investigated. We have succeeded in forming ultra shallow p+/n junction with junction depth of 8 nm and sheet resistance of 920 Ω/.

Evaluation of ion implantation charging by using EEPROM

Abstract Ion implantation charging has been studied by evaluation of the threshold voltage shift (ΔVt) of EEPROM devices. The threshold voltage shifted proportionally with the variation of the electron emission current. This method allows the uniformity of charging within a wafer to be evaluated exactly, and has also shown excellent repeatability. The oxide breakdown frequency of the MOS capacitor showed good agreement with the threshold voltage shift. Consequently, the EEPROM threshold voltage shift measurement was found to be very useful in the development of systems which retard charge buildup.

Ultra‐Shallow P+/N Junction Formation in Si Using Low Temperature Solid Phase Epitaxy Assisted with Laser Activation

A combination of Ge pre‐amorphization implantation (Ge‐PAI), low‐energy B implantation and laser annealing is a promising method to form highly‐activated, abrupt and ultra‐shallow junctions (USJ). In our previous report of IIT 2006, we succeeded in forming pn junctions less than 10 nm using non‐melt double‐pulsed green laser. However, a large leakage current under reverse bias was observed consequently due to residual defects in the implanted layer. In this study, a method to form USJ is proposed: a combination of low‐temperature solid phase epitaxy and non‐melt laser irradiation for B activation. Ge pre‐amorphization implantation was performed at energy of 6 keV with a dose of 3×1014/cm2. Then B implantation was performed at energy of 0.2 keV with a dose of 1.2×1015/cm2. Samples were annealed at 400 °C for 10 h in nitrogen atmosphere. Subsequently, non‐melt laser irradiation was performed at energy of 690 mJ/cm2 and pulse duration of 100 ns with intervals of 300 ns. As a result, USJ around 10 nm with bet...

New Delineation Of Process-Induced Micro-Defects Using Anodic Oxidation

A new observation technique for process-induced micro-defects in ULSI using a combination of anodic oxidation and chemical removal of the oxide has been developed. Enhanced oxidation has occurred at the defect region due to the stress field and then craterlike delineation has been formed after oxide removal. AFM and SEM observation of the micro defects induced by ion implantation and applications using this technique to the failure analysis of MOS device fabrication are presented.