Analysis of analog parameters in NW-TFETs with Si and SiGe source composition at high temperatures

Bordallo, Caio Cesar Mendes; Martino, João Antônio; Agopian, Paula Ghedini Der; Rooyackers, R.; Vandooren, A.; Thean, A.; Simoen, Eddy; Claeys, Cor

doi:10.1109/sbmicro.2015.7298148

Cited by 8 publications

(6 citation statements)

References 13 publications

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“…Device research has shifted toward new architectures, materials, and technologies to enable "More than Moore" paradigms, [4] extending the mature Si complementary metal-oxidesemiconductor (CMOS) platform. [5] In this regard, Si 1−x Ge x and Ge active regions integrated on Si platforms are promising candidates for future optoelectronic devices [6] and the realization of energy efficient steep subthreshold switches such as band-to-band tunneling transistors (TFETs), [7,8] negative capacitance Ge nanowire FETs, [9,10] and positive feedback FETs. [11] Conventionally, degenerately doped semiconductor regions in combination with thin layers made of transition-metal semiconductor alloys, such as metalsilicides [12] and metal-germanides, [13] have been used to obtain ohmic contacts to most Si 1−x Ge x and Ge based devices.…”

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confidence: 99%

Composition Dependent Electrical Transport in Si_1−xGe_xNanosheets with Monolithic Single‐Elementary Al Contacts

Wind

Sistani

Böckle

et al. 2022

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and drain electrodes in highly scaled p-channel field-effect transistors (FETs) for the realization of very-large-scale integration (VLSI) systems. [1] Despite these efforts, the continuous scaling of metaloxide-semiconductor field-effect transistors (MOSFETs) is approaching physical limits where the nature of deterministic charge carrier separation between source and drain by an energy barrier is not applicable anymore. [2,3] In the quest of overcoming scaling limitations, new lines of research arose. Device research has shifted toward new architectures, materials, and technologies to enable "More than Moore" paradigms, [4] extending the mature Si complementary metal-oxidesemiconductor (CMOS) platform. [5] In this regard, Si 1−x Ge x and Ge active regions integrated on Si platforms are promising candidates for future optoelectronic devices [6] and the realization of energy efficient steep subthreshold switches such as band-to-band tunneling transistors (TFETs), [7,8] negative capacitance Ge nanowire FETs, [9,10] and positive feedback FETs. [11] Conventionally, degenerately doped semiconductor regions in combination with thin layers made of transition-metal semiconductor alloys, such as metalsilicides [12] and metal-germanides, [13] have been used to obtain ohmic contacts to most Si 1−x Ge x and Ge based devices. Toward the achievement of ohmic contacts, pinning-free metal semiconductor contacts have been explored in Si and Ge through Si 1−x Ge x is a key material in modern complementary metal-oxide-semiconductor and bipolar devices. However, despite considerable efforts in metal-silicide and -germanide compound material systems, reliability concerns have so far hindered the implementation of metal-Si 1−x Ge x junctions that are vital for diverse emerging "More than Moore" and quantum computing paradigms. In this respect, the systematic structural and electronic properties of Al-Si 1−x Ge x heterostructures, obtained from a thermally induced exchange between ultrathin Si 1−x Ge x nanosheets and Al layers are reported. Remarkably, no intermetallic phases are found after the exchange process. Instead, abrupt, flat, and void-free junctions of high structural quality can be obtained. Interestingly, ultra-thin interfacial Si layers are formed between the metal and Si 1−x Ge x segments, explaining the morphologic stability. Integrated into omega-gated Schottky barrier transistors with the channel length being defined by the selective transformation of Si 1−x Ge x into single-elementary Al leads, a detailed analysis of the transport is conducted. In this respect, a report on a highly versatile platform with Si 1−x Ge x composition-dependent properties ranging from highly transparent contacts to distinct Schottky barriers is provided. Most notably, the presented abrupt, robust, and reliable metal-Si 1−x Ge x junctions can open up new device implementations for different types of emerging nanoelectronic, optoelectronic, and quantum devices.

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confidence: 99%

Composition Dependent Electrical Transport in Si_1−xGe_xNanosheets with Monolithic Single‐Elementary Al Contacts

Wind

Sistani

Böckle

et al. 2022

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“…Starting from a substrate with high arsenic doping which is used as the drain, the channel and source are obtained by blanket epitaxial growth, for the NW TFET (NW-TFET) the source is obtained with a in situ borondoped SiGe layer [20], while for the NW MOSFET (NW-MOSFET) arsenic is used [21], detailed information about the fabrication can be found in [21]. The use of SiGe in the source increases the drain current preserving the good analog behavior [22,23].…”

Section: Devices Overviewmentioning

confidence: 99%

Hybrid low-dropout voltage regulator designed with TFET-MOSFET nanowire technologies

Tolêdo

Martino

Agopian

2023

Semicond. Sci. Technol.

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In this work, hybrid low-dropout voltage regulators (LDO) designed with a TFET-MOSFET nanowire (NW) technologies are presented. The devices were modeled using Verilog-A with lookup tables based on experimental data of NW-TFETs and NW-MOSFETs fabricated in the same silicon vertical process flow. In all LDOs, the amplifier devices were biased with the same gm/ID = 9.5 V-1 for a maximum load current/capacitance of 1 mA/1 nF. In the hybrid regulators, the power transistors are designed with NW-MOSFETs to deliver the high load current, while the other devices are implemented with NW-TFET to provide high gain and low power consumption. Due to different onset voltages, two hybrid LDOs are proposed, one with symmetrical onset voltages implemented with a voltage shift (Hybrid-ΔV LDO) and one with a level-shift stage using the real characteristics of the devices (Hybrid-LS LDO). The hybrid circuits were compared to LDOs designed using only NW-TFETs and with only NW-MOSFETs. The Hybrid-ΔV LDO presents the best loop gain (62 dB) with a low quiescent current (7 nA), while the Hybrid-LS LDO shows a good gain-bandwidth product (700 Hz). In the transient analysis, the hybrid circuits showed a settling time close to the NW-MOSFETLDO but with higher undershoot/overshoot values in the case of a load transient. As demonstrated, the use of hybrid projects with TFET-MOSFET nanowire technologies enable LDOs with ultra-low power consumption and high loop gain, that are presented on TFET circuits and with a frequency response equivalent of MOSFET circuits.

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“…The measured MOSFETs have only Si in the channel, source, and drain regions. The isolated characteristics of the transistors have already been extensively studied in previous works [21][22][23][24][25][26]. A schematic of the devices is shown in figure 1.…”

Section: Devices Descriptionmentioning

confidence: 99%

“…The transistors used in this study have already been extensively studied at a device level [18][19][20][21][22][23][24][25][26], but not at circuit level. Therefore, a simple, well-known topology was chosen so that the characteristics of the different devices and its effects in the OTA performance can be analyzed without worries about circuit complexity.…”

Section: Introductionmentioning

confidence: 99%

Operational transconductance amplifier designed with nanowire tunnel-FET with Si, SiGe and Ge sources using experimental data

Nogueira

Agopian

Martino

2020

Semicond. Sci. Technol.

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In this paper operational transconductance amplifiers (OTA) were designed with nanowire (NW) tunnel field effect transistors (TFET) with different source materials (Si, SiGe, and Ge) and compared with NW Si MOSFET devices. Lookup tables with experimental data were used to model the transistors and simulate the OTAs. At the same dimensions and transistor efficiency region, the TFET OTAs have larger gain than the MOSFET circuit. The Ge-source TFET OTA presents the highest differential gain (105 dB), followed by the Si TFET (96 dB) and the SiGe-source TFET (90 dB), with the MOSFET presenting the lowest gain (51 dB). However, the MOSFET has the best gain-bandwidth product (GBW) (9.2 MHz) followed by the Ge-source TFET (1.6 MHz), the SiGe-source TFET (900 kHz) and the Si TFET (41 kHz). The second group of OTAs, where the same power consumption was considered and where the gain of the MOSFET OTA and the GBW of the TFETs' circuits were increased was also studied. The gain of the MOSFET OTA increased to 56 dB, but it is still lower than the TFET circuits (96, 90 and 102 dB for the Si TFET, SiGe-source TFET and Ge-source TFET, respectively). The GBW of the Si TFET, SiGe-source TFET and Ge-source TFET circuits increased to 71 kHz, 1 MHz, and 2 MHz, respectively. Nevertheless, the MOSFET OTA has the best GBW (4.7 MHz) again but being just 2.35 times the GBW of the Ge-source TFET case. Therefore, because of the high gain of the TFETs OTAs, they are indicated for low power, low-frequency applications, with the Ge-source TFET presenting a good compromise between gain and GBW. The circuits' linearity was also verified, and they demonstrate to be more dependent on bias choices than on the devices themselves.

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Analysis of analog parameters in NW-TFETs with Si and SiGe source composition at high temperatures

Cited by 8 publications

References 13 publications

Composition Dependent Electrical Transport in Si_1−xGe_xNanosheets with Monolithic Single‐Elementary Al Contacts

Composition Dependent Electrical Transport in Si_1−xGe_xNanosheets with Monolithic Single‐Elementary Al Contacts

Hybrid low-dropout voltage regulator designed with TFET-MOSFET nanowire technologies

Operational transconductance amplifier designed with nanowire tunnel-FET with Si, SiGe and Ge sources using experimental data

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Analysis of analog parameters in NW-TFETs with Si and SiGe source composition at high temperatures

Cited by 8 publications

References 13 publications

Composition Dependent Electrical Transport in Si1−xGexNanosheets with Monolithic Single‐Elementary Al Contacts

Composition Dependent Electrical Transport in Si1−xGexNanosheets with Monolithic Single‐Elementary Al Contacts

Hybrid low-dropout voltage regulator designed with TFET-MOSFET nanowire technologies

Operational transconductance amplifier designed with nanowire tunnel-FET with Si, SiGe and Ge sources using experimental data

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Product

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Composition Dependent Electrical Transport in Si_1−xGe_xNanosheets with Monolithic Single‐Elementary Al Contacts

Composition Dependent Electrical Transport in Si_1−xGe_xNanosheets with Monolithic Single‐Elementary Al Contacts