THz operation of asymmetric-nanochannel devices

Balocco, Claudio; Halsall, Matthew P.; Vịnh, Nguyễn Quang; Song, Aimin

doi:10.1088/0953-8984/20/38/384203

Cited by 57 publications

(47 citation statements)

References 18 publications

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“…, where V is the applied DC bias and I is the current from I-V curves [22], are listed in Table I. Both Gd and G'd of the SSD with PMMA as mask are much lower than the devices with hard masks.…”

Section: B Different Masks On the Properties Of Ssdsmentioning

confidence: 99%

A Novel Thermally Evaporated Etching Mask for Low-Damage Dry Etching

Wang

Zhu

et al. 2017

IEEE Trans. Nanotechnology

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Abstract-Dry etching is widely used for nanofabrication and it requires reliable etching masks. However, hard dry etching masks usually need high-temperature and/or plasma deposition, which may causes damage to temperature-sensitive materials and semiconductor surface. Here, we develop a novel etching mask material, silicon monoxide (SiO), which is thermally evaporated and hence can avoid such drawbacks. The etching selectivity of evaporated SiO is shown to be higher than 50:1, comparable to sputtered SiO2. A nanochannel device, called self-switching diode (SSD), is fabricated to evaluate the mask-deposition-process damage because of its high sensitivity to the process damage. In comparison to commonly used sputtered SiO2 and polymethyl methacrylate (PMMA) mask, the SSD fabricated using evaporated SiO exhibit the highest channel conductance, strongest nonlinearity, and best high-frequency performance. Hall measurements also reveal that the carrier mobility of nanochannels etched with SiO mask is twice that of similar channels with SiO2 mask.

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Section: B Different Masks On the Properties Of Ssdsmentioning

confidence: 99%

A Novel Thermally Evaporated Etching Mask for Low-Damage Dry Etching

Wang

Zhu

et al. 2017

IEEE Trans. Nanotechnology

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“…This is what a Monte Carlo simulation does. Because of the limitations of the computational resources, and the fact that the transported carriers form a 2DEG, we use a 2D simulator [4,[6][7][8]. In the In 0.53 Ga 0.47 As/In 0.53 Al 0.47 As structure, the simulated layer is the active layer of 2DEG, and its geometrical structure is shown in Figure 1.…”

Section: Monte Carlo Simulation For Ssdmentioning

confidence: 99%

“…Most previous studies investigated SSDs at the microscale [4][5][6][7]9,10]. At this scale, the maximum average drift velocity of the electrons is about (2-3)×10 7 cm/s [10].…”

Section: Monte Carlo Simulation For Ssdmentioning

confidence: 99%

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Ballistic transport in nanoscale self-switching devices

Chen

Zheng

et al. 2011

Chin. Sci. Bull.

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Using the Monte Carlo method, a type of semiconductor nano-device called self-switching device (SSD), which has diode-like I-V characteristics, was simulated. After analyzing the microscopic transport behavior of the carriers, we show that the ballistic effects exist in the SSDs when the channel length of the device is extremely short (~120 nm). Furthermore, we show that the ballistic effect doubles the average drift velocity of the carriers (to ~6.0×10 7 cm/s) in short-channel SSDs, which decreases the transit time. This implies that when the dimensions are decreased to nanoscale length, the SSD can operate much faster because the ballistic effect increases the operation speed of the device. Moreover, because of the ballistic transport, the energy efficiency may also be improved. During the last two decades, the dimensions of compound semiconductor devices have become smaller. Electronic devices at micrometer and nanometer scale have attracted increasing attention [1][2][3]. In 2003, using an asymmetric structure, Song et al. designed a novel device with diodelike I-V characteristics, which was called a self-switching device (SSD) [4]. The fabrication of SSD is remarkably simple, and only requires one etching step to produce the two required insulating trenches. This simplicity makes it possible to downscale the geometrical dimensions of the device to nanoscale, which increases its cut-off frequency. It has been reported that a SSD can operate at a frequency over 110 GHz at room temperature [5] and at 2.5 THz at 150 K [6]. SSDs are fabricated using modulation-doped quantum well structures such as InGaAs/InP and InGaAs/InAlAs, in which the carriers transported in the active layer form two dimensional electron gas (2DEG). After the growth of each layer, only two insulating L-shaped trenches (with a width *Corresponding author (email: stswangg@mail.sysu.edu.cn) of d and a length of L) along the direction perpendicular to the surface needed to be etched. This etching can be done using high-resolution lithography (as shown in Figure 1). Between these two trenches, there is a channel with a width of W in which the electrons are transported.When in operation, the left side is grounded and a bias voltage is applied to the right side. The diode-like I-V characteristics were simulated using the Monte Carlo method in this paper. It has been shown [4,7,8] that the electrical properties of a SSD are partially determined by its geometrical structure. Increasing either the width of the channel, W, or the trenches, d, will decrease the threshold voltage of the SSD (but not decrease it below zero). These parameters also influence the drain current when the reverse bias voltage is applied. This means that, as a switching device, the threshold voltage of a SSD is adjustable. If the geometrical parameters W, d or L are chosen properly, the threshold voltage can be set to zero.It has been suggested that SSDs have a diode-like I-V characteristics because of the field effects resulting from the charging regions near the channel [9...

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“…SSDs based on silicon are also perfectly viable; nevertheless the use of high mobility semiconductors like InGaAs implies larger electron velocities and therefore higher operation frequencies. In fact, experiments have demonstrated microwave detection up to 110 GHz at room temperature [2] and up to 2.5 THz at 10 K (dropping in the response above 70 K) [3] for InGaAs SSDs. Monte Carlo (MC) simulations [4] the behavior of the device and foresee working frequencies of above 1 THz.…”

Section: Introduction and Purposementioning

confidence: 99%