Deok-Ho Cho

The low-frequency noise characteristics of p-type metal-oxide-semiconductor field effect transistors with a strained-Si0.88Ge0.12 channel grown on bulk Si and a PD-SOI substrate

Low-frequency noise properties have been investigated for SiGe p-type metal-oxide- semiconductor field effect transistors with different substrates using Si bulk and a partially depleted silicon-on-insulator (PD SOI). The electrical properties of SiGe PD SOI were enhanced in the subthreshold slope and drain induced barrier lowering. However, the low-frequency noise for the PD SOI was found to degrade significantly in terms of the power spectral density. The low frequency noise was observed to follow the typical 1/fγ(γ = 1) dependence in SiGe bulk devices, but abnormal changes with γ = 2 were revealed in the SiGe PD SOI. The difference of the noise frequency exponent was mainly attributed to generation–recombination by traps presented at the silicon–oxide interface of the SOI. Regardless of the degraded noise performance in the SOI structure, the low-frequency noise level remained well at an acceptable level by virtue of the effective carrier confinement in the SiGe channel.

Bidirectional Transient Voltage Suppression Diodes for the Protection of High Speed Data Line from Electrostatic Discharge Shocks

A bidirectional transient voltage suppression (TVS) diode consisting of specially designed p--n++-p-multi-junctions was developed using low temperature (LT) epitaxy and fabrication processes. Its electrostatic discharge (ESD) performance was investigated using IV, C-V, and various ESD tests including the human body model (HBM), machine model (MM) and IEC 61000-4-2 (IEC) analysis. The symmetrical structure with very sharp and uniform bidirectional multijunctions yields good symmetrical I-V behavior over a wide range of operating temperature of 300 K ? 450 K and low capacitance as 6.9 pF at 1 MHz. In addition, a very thin and heavily doped n++ layer enabled I-V curves steep rise after breakdown without snapback phenomenon, then resulted in small dynamic resistance as 0.2 ;, and leakage current completely suppressed down to pA. Manufactured bidirectional TVS diodes were capable of withstanding ± 4.0 kV of MM and ± 14 kV of IEC, and exceeding ± 8 kV of HBM, while maintaining reliable I-V characteristics. Such an excellent ESD performance of low capacitance and dynamic resistance is attributed to the abruptness and very unique profiles designed very precisely in p-n++p-multi-junctions.

Correlation of reverse leakage current conduction mechanism and electrostatic discharge robustness of transient voltage suppression diode

Five transient voltage suppression (TVS) diodes with breakdown voltages (BV) of 6, 7, 11, 13 and 15 V have been developed using low-temperature (LT) epitaxy technology and an LT fabrication process. The electrostatic discharge (ESD) performance and temperature dependency of reverse leakage current are investigated by applying the IEC61000-4-2 (IEC) standard and an I-V-T analysis. The TVS diodes exhibited excellent ESD robustness, exceeding the standard ESD requirement of IEC level 4, 8 kV in contact discharge, while also maintaining the reverse leakage current level below 10−9 A. Excellent ESD performance was found to be relevant for lower breakdown voltage TVS diodes. The reverse leakage currents showed substantial changes in thermal activation energy from 0.43 to 0.6 eV with respect to BV control from 6 to 15 V. The increased activation energy at high BV was attributed to the transition of the conduction mechanism from tunneling mode to generation-recombination mode. The reduction of reverse leakage current from a generation-recombination to tunneling conduction mechanism is expected to improve the ESD performance of TVS diodes.

ESD robustness of low-voltage/high-speed TVS devices with epitaxial grown films

A transient voltage suppression (TVS) diode with abrupt junctions has been developed using the low-temperature epitaxy and process technology. The triggering voltage at 6 V could be precisely controlled by the thickness and dopant concentration. The reliability of TVS device is confirmed based on its electrostatic discharge (ESD) strength in conjunction with the transmission line pulse (TLP) test. As a result, the device could exceed 28 A TLP, ±8 kV MM, and could withstand IEC 61000-4-2 up to ±19kV. Moreover, TVS diode exhibited very low leakage current, small capacitance, fast respond time and high cut off frequency of 2nA, 60 pF, 8 ps, and 52 MHz, respectively. TVS diode can be also used for a digital communication line as well as an ESD/EMI filter attenuating the RF noise in MHz range.

High Performance ESD/Surge Protection Capability of Bidirectional Flip Chip Transient Voltage Suppression Diodes

Copyright ©2016 KIEEME. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. pISSN: 1229-7607 eISSN: 2092-7592 DOI: http://dx.doi.org/10.4313/TEEM.2016.17.4.196 OAK Central: http://central.oak.go.kr

Transmission line pulse properties for a bidirectional transient voltage suppression diode fabricated using low-temperature epitaxy

Based on low temperature epitaxy technology, a bidirectional transient voltage suppression (TVS) diode with abrupt multi-junctions was developed. The bidirectional triggering voltage of ±16 V was controlled by the thickness and dopant concentration in the multi-junctions using a reduced-pressure chemical vapor deposition (RPCVD) process. The manufactured TVS diode showed a small leakage current density and dynamic resistance of less than 5.1 × 10-14 A/µm2 and 1 O, respectively, which could be associated with the epitaxially grown abrupt multijunctions. The transmission line pulse (TLP) analysis results demonstrated that the bidirectional TVS diodes were capable of withstanding a peak pulse current of up to ±20 A or ±1.02 × 10-3 A/µm2, which is equivalent to ±40 kV of the human body model (HBM) and ±12 kV of IEC61000-4-2 (IEC). Nevertheless, the electrostatic discharge (ESD) design window showed that bidirectional TVS diodes meet IEC level 4 standard ESD protection requirements (8 kV in contact discharge). In addition, because of the bidirectional structure, the TVS devices exhibited a small capacitance of 4.9 pF, which confirms that the TVS diode can be used for protecting high data rate communication lines (over 500 Mbps) from ESD shock.

Novel Punch-through Diode Triggered SCR for Low Voltage ESD Protection Applications

This research presented the concept of employing the punch-through diode triggered SCRs (PTTSCR) for low voltage ESD applications such as transient voltage suppression (TVS) devices. In order to demonstrate the better electrical properties, various traditional ESD protection devices, including a silicon controlled rectifier (SCR) and Zener diode, were simulated and analyzed by using the TCAD simulation software. The simulation result demonstrates that the novel PTTSCR device has better performance in responding to ESD properties, including DC dynamic resistance and capacitance, compared to SCR and Zener diode. Furthermore, the proposed PTTSCR device has a low reverse leakage current that is below 10 -12 A, a low capacitance of 0.07 fF/㎛², and low triggering voltage of 8.5 V at 5.6×10 -5 A. The typical properties couple with the holding voltage of 4.8 V, while the novel PTTSCR device is compatible for protecting the low voltage, high speed ESD protection applications. It proves to be good candidates as ultra-low capacitance TVS devices.

Effects of Electrostatic Discharge Stress on Current-Voltage and Reverse Recovery Time of Fast Power Diode

Fast recovery diodes (FRDs) were developed using the epitaxial layers grown by low temperature epitaxy technology. We investigated the effect of electrostatic discharge (ESD) stresses on their electrical and switching properties using current-voltage (I-V) and reverse recovery time analyses. The FRDs presented a high breakdown voltage, >450 V, and a low reverse leakage current, A. From the temperature dependence of thermal activation energy, the reverse leakage current was dominated by thermal generation-recombination and diffusion, respectively, at low and high temperature regions. By virtue of the abrupt junction and the Pt drive-in for the controlling of carrier lifetime, the soft reverse recovery behavior could be obtained along with a well-controlled reverse recovery time of 21.12 ns. The FRDs exhibited excellent ESD robustness with negligible degradations in the I-V and the reverse recovery characteristics up to kV of HBM and kV of IEC61000-4-2 shocks. Likewise, transmission line pulse (TLP) analysis reveals that the FRDs can handle the maximum peak pulse current, , up to 30 A in the forward mode and down to - 24 A in the reverse mode. The robust ESD property can improve the long term reliability of various power applications such as automobile and switching mode power supply.

Development of LC-type ESD/EMI filter based on TVS devices for peripheral device applications

A fully integrated LC-type ESD/EMI filter was developed by the integrated passive devices (IPD) technology. Unique TVS diodes are employed to enhance its performance while maintaining robust ESD characteristics. The reliability and performance of ESD/EMI filter are confirmed based on both attenuation and electrostatic discharge (ESD) strength which could be evaluated by insertion loss (S parameter), ESD and transmission line pulse (TLP) testing method. As the results, the device shows very low leakage current less than 1nA. Its ESD protection and attenuation could be robustness exceed 28 A TLP and ±17 kV IEC 61000-4-2 and achieved as >;35 dB at 800 MHz ~3 GHz, respectively. The cut off frequency obtained of 160 MHz that can ensure high-speed data communication applications.

Comparison of Electrical Characteristics of SiGe pMOSFETs Formed on Bulk-Si and PD-SOI

This paper has demonstrated the electrical properties of SiGe pMOSFETs fabricated on both bulk-Si and PD SOI substrates. Two principal merits, the mobility increase in strained-SiGe channel and the parasitic capacitance reduction of SOI isolation, resulted in improvements in device performance. It was observed that the SiGe PD SOI could alleviate the floating body effect, and consequently DIBL was as low as 10 mV/V. The cut-off frequency of device fabricated on PD SOI substrate was roughly doubled in comparison with SiGe bulk: from 6.7 GHz to 11.3 GHz. These experimental result suggests that the SiGe PD SOI pMOSFET is a promising option to drive CMOS to enhance performance with its increased operation frequency for high speed and low noise applications.