• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.721-724
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• 2011

Polymer base organic PN junction with various ion types was studied. Low-energy ion implantation technique(~keV) is very useful in physical doping on PPP(Polyparaphenylene) polymer. By double implantation, effective organic PN junction was achieved. The best obtained electrical I-V property was rectification ratio which was about 10000. However, still have problems in low junction current density.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.1-7
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• 2006

3-dimensional(3-D) simulations of ideal double-gate bulk FinFET were performed extensively and the electrical characteristics. were analyzed. In 3-D device simulation, we changed gate length($L_g$), height($H_g$), and channel doping concentration($N_b$) to see the behaviors of the threshold voltage($V_{th}$), DIBL(drain induced barrier lowering), and SS(subthreshold swing) with source/drain junction depth($X_{jSDE}$). When the $H_g$ is changed from 30 nm to 45nm, the variation gives a little change in $V_{th}$(less than 20 mV). The DIBL and SS were degraded rapidly as the $X_{jSDE}$ is deeper than $H_g$ at low fin body doping($1{\times}10^{16}cm^{-3}{\sim}1{\times}10^{17}cm^{-3}$). By adopting local doping at ${\sim}10nm$ under the $H_g$, the degradation could be suppressed significantly. The local doping also alleviated $V_{th}$ lowering by the shallower $X_{jSDE}\;than\;H_g$ at low fin body doping.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.713-716
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• 2013

The device performances of N-channel Tunneling FET have been characterized with different intrinsic length between drain and gate($L_{in}$), drain and source doping, permittivity and oxide thickness when the total effective channel length is constant. N-channel Tunneling FET of SOI structure have been used in characterization. $L_{in}$ was from 30nm to 70nm, dose concentration of drain and source were from $2{\times}10^{12}cm^{-2}$ to $2{\times}10^{15}cm^{-2}$ and from $1{\times}10^{14}cm^{-2}$ to $3{\times}10^{15}cm^{-2}$, permittivity was from 3.9 to 29, and oxide thickness was from 3nm to 9nm. The device performances were characterized by Subthreshold slope(S-slope), On/off ratio, and leakage current. From the simulation results, the leakage current have been reduced for long $L_{in}$ and low drain doping. S-slope have been reduced for high source doping, high permittivity and thin oxide thickness. With considering the leakage current and S-slope, it is desirable that are long $L_{in}$, low drain doping, high source doping, high permittivity and thin oxide thickness to optimize device performance in n-channel Tunneling FET.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.509-514
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• 2020

The two key variables of an Si solar cell, i.e., emitter (n-type window layer) and base (p-type substrate) doping levels or concentrations, are studied using Medici, a 2-dimensional semiconductor device simulation tool. The substrate is p-type and 150 ㎛ thick, the pn junction is 2 ㎛ from the front surface, and the cell is lit on the front surface. The doping concentration ranges from 1 × 10¹⁰ cm^-3 to 1 × 10²⁰ cm^-3 for both emitter and base, resulting in a matrix of 11 by 11 or a total of 121 data points. With respect to increasing donor concentration (Nd) in the emitter, the open-circuit voltage (Voc) is little affected throughout, and the short-circuit current (Isc) is affected only at a very high levels of Nd, exceeding 1 × 10¹⁹ cm^-3, dropping abruptly by about 12%, i.e., from Isc = 6.05 × 10^-9 A·㎛^-1, at Nd = 1 × 10¹⁹ cm^-3 to Isc = 5.35 × 10^-9 A·㎛^-1 at Nd = 1 × 10²⁰ cm^-3, likely due to minority-carrier, or hole, recombination at the very high doping level. With respect to increasing acceptor concentration (Na) in the base, Isc is little affected throughout, but Voc increases steadily, i.e, from Voc = 0.29 V at Na = 1 × 10¹² cm^-3 to 0.69 V at Na = 1 × 10¹⁸ cm^-3. On average, with an order increase in Na, Voc increases by about 0.07 V, likely due to narrowing of the depletion layer and lowering of the carrier recombination at the pn junction. At the maximum output power (Pmax), a peak value of 3.25 × 10^-2 W·cm^-2 or 32.5 mW·cm^-2 is observed at the doping combination of Nd = 1 × 10¹⁹ cm^-3, a level at which Si is degenerate (being metal-like), and Na = 1 × 10¹⁷ cm^-3, and minimum values of near zero are observed at very low levels of Nd ≤ 1 × 10¹³ cm^-3. This wide variation in Pmax, even within a given kind of solar cell, indicates that selecting an optimal combination of donor and acceptor doping concentrations is likely most important in solar cell engineering.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.2
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• pp.73-77
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• 2021

Ga-doped ZnO thin films by RF magnetron sputtering process were synthesized according to the deposition conditions of O2 and Ar atmosphere gases, and rapid heat treatment (RTA) was performed at 600℃ in an N2 atmosphere. The thickness of the deposited ZnO : Ga thin film was measured, the crystal phase was investigated by XRD pattern analysis, and the microstructure of the thin film was observed by FE-SEM and AFM images. The intensity of the (002) plane of the X-ray diffraction pattern showed a significant difference depending on the deposition conditions of the thin films formed by O2 and Ar atmosphere gas types. In the case of a single thin f ilm doped with Ga under O2 conditions, a strong diffraction peak was observed. Under O2 and Ar conditions, in the case of a multilayer thin film with Ga doping, only a peak on the (002) plane with a somewhat weak intensity was shown. In the FE-SEM image, it was observed that the grain size of the surface of the thin film slightly increased as the thickness increased. In the case of a multilayer thin film with Ga doping under O2 and Ar atmosphere conditions, the specific resistance was 6.4 × 10-4 Ω·cm. In the case of a single thin film with Ga doping under O2 atmosphere conditions, the resistance of the thin film decreased. The resistance decreased as the thickness of the Ga-doped ZnO thin film increased to 2 ㎛, showing relatively a low specific resistance of 1.0 × 10-3 Ω·cm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.285-290
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• 2015

The phase change memory material is an active element in phase change memory and exhibits reversible phase transition behavior by thermal energy input. The doping of the phase change memory material with Ga leads to the increase of its crystallization temperature and the improvement of its amorphous stability. In this study, we investigated the effect of GaGe sputtering power on the formation of the phase change memory material including Ga. The deposition rate linearly increased to a maximum of 127 nm and the surface roughness remained uniform as the GaGe sputtering power increased in the range from 0 to 75 W. The Ga concentration in the thin film material abruptly increased at the critical sputtering power of 60 W. This influence of GaGe sputtering power was confirmed to result from a combined sputtering-evaporation process of Ga occurring due to the low melting point of Ga ($29.77^{\circ}C$).

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.192-198
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• 2017

In this paper, we propose a novel double gate vertical channel tunneling field effect transistor (DVTFET) with a dielectric sidewall and optimization characteristics. The dielectric sidewall is applied to the gate region to reduced ambipolar voltage ($V_{amb}$) and double gate structure is applied to improve on-current ($I_{ON}$) and subthreshold swing (SS). We discussed the fin width ($W_S$), body doping concentration, sidewall width ($W_{side}$), drain and gate underlap distance ($X_d$), source doping distance ($X_S$) and pocket doping length ($X_P$) of DVTFET. Each of device performance is investigated with various device parameter variations. To maximize device performance, we apply the optimum values obtained in the above discussion of a optimization simulation. The optimum results are steep SS of 32.6 mV/dec, high $I_{ON}$ of $1.2{\times}10^{-3}A/{\mu}m$ and low $V_{amb}$ of -2.0 V.

• Korean Journal of Materials Research
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• v.15 no.5
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• pp.313-317
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• 2005

The relation between bulk microdefect (BMD) and mechanical strength of $P/P^-$ epitaxial silicon wafers (Epitaxial wafer) as a function of nitrogen concentrations was studied. After 2 step anneal$(800^{\circ}C/4hrs+1000^{\circ}C/16hrs)$, BMD was not observed in nitrogen undoped epitaxial silicon wafer while BMD existed and increased up to $3.83\times10^5\;ea/cm^2$ by addition of $1.04\times10^{14}\;atoms/cm^3$ nitrogen doping. The slip occurred for nitrogen undoped and low level nitrogen doped epitaxial wafers. However, there was no slip occurrence above $7.37\times10^{13}\;atoms/cm^3$ nitrogen doped epitaxial wafer. Mechanical strength was improved from 40 to 57 MPa as nitrogen concentrations were increased. Therefore, the nitrogen doping in silicon wafer plays an important role to improve BMD density, slip occurrence and mechanical strength of the epitaxial silicon wafers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.637-640
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• 2009

In this work, we demonstrate 800 V 4H-SiC power DMOSFETs with several structural alterations to obtain a low threshold voltage ($V_{TH}$) and a high figure of merit ($V_B\;^2/R_{SP,ON}$), To optimize the device performance, we consider four design parameters; (a) the doping concentration ($N_{CSL}$) of current spreading layer (CSL) beneath the p-base region, (b) the thickness of p-base ($t_{BASE}$), (c) the doping concentration ($N_J$) and width ($W_J$) of a JFET region, (d) the doping concentration ($N_{EPI}$) and thickness ($t_{EPI}$) of epi-layer. These parameters are optimized using 2D numerical simulation and the 4H-SiC DMOSFET structure results in a threshold voltage ($V_{TH}$) below $^{\sim}$3.8 V, and high figure of merit ($V_B\;^2/R_{SP,ON}$>$^{\sim}$200 $MW/cm^2$) for a power MOSFET in $V_B\;^{\sim}$800 V range.

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.760-765
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• 2008

In this study, the effects of small amounts (${\leq}3\;mol%$) of Li doping on the sintering characteristics and electrochemical performance of $(ZrO_2)_{0.89}(ScO_{1.5})_{0.1}(CeO_2)_{0.01}$ (ScSZ) were investigated. By adding 3 mol% lithium, the densification temperature of ScSZ was reduced from the conventional temperature of $1400^{\circ}C$ to $1200^{\circ}C$. It was found that Li doping also led to changes in the Zr:Sc ratio at the grain boundaries. Correspondingly, the dispersion of lithium zirconia at the grain boundaries accelerated the growth of ScSZ grains and increased the grain boundary resistance at temperatures below $450^{\circ}C$. At elevated temperatures of $450{\sim}750^{\circ}C$, the electrical conductivity of the ScSZ after doping remained almost unchanged under air and reducing atmospheres. These results suggest that the addition of lithium is promising for use in low temperature co-firing of ScSZ-based components for intermediate temperature solid oxide fuel cells.