Electrical properties of nanometer-scale Si p+-n junctions fabricated by low energy Ga+ focused ion beam implantation

Abstract

Diodes have been fabricated by on-axis Ga+ focused ion beam (FIB) implantation at 4–25 keV into n-Si 〈100〉 wafers doped to 2×1015/cm3. Post-implantation anneal was performed at 600 °C for 30 s to electrically activate the Ga and to regrow the implanted layer. SIMS measurements performed to obtain the Ga concentration depth profile indicate good agreement with trim simulation even at low energies. At 4 keV an electrical junction depth of 15 nm is obtained from spreading resistance profiling (SRP). The junction depth was found to vary linearly with energy over the range explored. The electrical properties of the diodes were obtained from I-V characteristics. The leakage current density of the 5 keV diode was measured to be 1 and 20 nA/cm2 at a reverse bias of 1 and 5 V, respectively. The corresponding leakage current density values for the 10 and 15 keV diodes were between 25% and 50% lower than those reported for 5 keV. The reverse bias breakdown voltage was between 105 and 110 V for all diodes. The combination of nanometer-scale junction depth, low leakage current density, and high breakdown voltage indicate that low energy Ga FIB implantation is a promising technology for ultrashallow p+ -n junction fabrication.

Near-field scanning optical microscopy with monolithic silicon light emitting diode on probe tip

“…10,11 Ion doping with focused ion beams ͑FIB͒ allows for the creation of nanometer-sized P-N diodes. 12,13 LEDs employing InAs quantum dots in a FIB-created PN junction have also been reported. 14,15 In this paper, we used a FIB to create a nanometer-scale LED on a microfabricated silicon scanning probe tip.…”

Focused ion beam applications to solid state devices

“…GaAs (100 keV Ga + ) [87,88] Isolation [87,88] AlGaAs/GaAs (100 keV Ga + ) [89] Resonant tunneling [89] AlGaAs/InGaAs/GaAs (100 keV Ga + ) [90] Ballistic transport [90] AlGaAs/GaAs (30,100 keV Ga + ) [91] Quantum wire [91,92] InGaAs/InP (100 keV Ga + ) [92] GaAs/AlGaAs (150 keV Ga + ) [93] Nanostructure processing [93] GaAs/GaAlAs (20,100 keV Ga + ) [94][95][96] Mixing of quantum well [94] In-plane gated wire [95] In-plane gated SET [96] Si (5 keV Ga + ) [97] Si p-n junction [97] GaAs/AlGaAs (160 keV Si ++ ) [98] 2DEG formation [96] GaAs/AlGaAs (0.1 ∼ 1 keV Si ++ ) [99] electron waveguide [99] GaAs (140 keV Si ++ ) [100] Gun diode [100] Si (140 keV Si ++ ) [101] Selective epitaxy [101] GaAs (100 keV Si ++ , Be ++ ) [102] In-plane gated FET [102] AlGaAs/GaAs (35 keV Si ++ ) [103] Quantum wire [103] Si (220 keV As ++ ) [104] CCD [104] Si (75 keV Pd + ,Pd ++ ) [105] Silicide formation [105] (figure 6). These voids were found, from this result and other related information, to be caused by electromigration.…”

Characterization of p+-n Junctions and a Quasi-One-Dimensional Structure Fabricated by Low-Energy Focused Ion Beam

“…Although, the idea of using low-energy FIB to form shallow p-n junctions has been investigated in the past, the detailed studies on the I − V characteristics of the junctions had not been done yet [9][10]. Since FIB has large beam current density, more defects are expected along with other possible unknown side effects, which in turn would affect the I − V characteristics.…”