Using two layers of pentacene deposited at different substrate temperatures as the active material, we have fabricated photolithographically defined organic thin-film transistors (OTFTs) with improved field-effect mobility and subthreshold slope. These devices use gold source drain electrodes octadecyltrichlorosilane-treated silicon dioxide gate dielectric. The large 1.5 cm/sup 2//V-s, on/off current ratio larger than 10/sup 8/, near zero threshold voltage, slope less 1.6 V per decade. To...

The charge-carrier transport mechanism in the organic semiconductor pentacene is explored using thin-film transistor structures. variation of field-effect mobility with temperature differs from sample to sample, ranging thermally activated temperature-independent behavior. This result excludes hopping as fundamental thin films, and suggests that traps and/or contact effects may strongly influence observed characteristics. These results also indicate transistors not be appropriate vehicles...

Pentacene-based organic thin-film transistors (TFT's) with field-effect mobility as large 0.7 cm/sup 2//V/spl middot/s and on/off current ratio larger than 10/sup 8/ have been fabricated. Pentacene films deposited by evaporation at elevated temperature low-to-moderate deposition rates a high degree of molecular ordering micrometer-sized dendritic grains. Such yield TFT's mobility. Films low or flash small grains poor

Organic thin-film transistors using the fused-ring polycyclic aromatic hydrocarbon pentacene as active electronic material have shown mobility large 0.7 cm/sup 2//V-s and on/off current ratio larger than 10/sup 8/; both values are comparable to hydrogenated amorphous silicon devices. On other hand, these most organic TFT's an undesirably subthreshold slope. We show here that slope typically observed is not intrinsic property of semiconducting devices with similar possible.

In organic thin film transistors (OTFT), the morphology and microstructure of an has a strong impact on charge carrier mobility device characteristics. To have well-defined predictable morphology, it is necessary to adapt basic structure semiconducting molecules in way that results optimum crystalline packing motif. Here we introduce new molecular design feature for semiconductors provides optimized essential efficient charge-carrier transport. Thus, cyclohexyl end groups naphthalene diimide...

We report a solvent-induced phase transition in pentacene thin films, from “thin film” to bulk-like phase. X-ray diffraction indicates that as-deposited thermally evaporated films consist mainly of (001)-oriented with an elongated (001) plane spacing 15.5±0.1 Å, and minor amount 14.5±0.1 Å. When such are exposed solvents as acetone, isopropanol, or ethanol, the entire layer shifts abruptly bulk value this shift is accompanied by macroscopic change film morphology. While molecular ordering...

We report stable, high performance zinc oxide thin film transistors grown by an atmospheric pressure atomic layer deposition system. With all and processing steps kept at or below 200°C, the alumina gate dielectric shows low leakage (below 10−8A∕cm2) breakdown fields. Zinc in a bottom geometry yield on/off ratios above 108, near zero turn-on voltage, little no hysteresis, mobility greater than 10cm2∕Vs. passivation, shifts threshold voltage under bias stress compare favorably to those...

We report electron transport properties of modulation-doped Si/SiGe at 300 and 77 K. Record mobilities 2830 18 000 cm2/V s K, respectively, have been measured. Depending on the spacer layer thickness, sheet resistance Si channel is in range 2000–10 Ω/⧠ K 450–700 The low field drift velocity 2–3 (5–10) times higher than corresponding measured Si/SiO2 structures (77 K). saturation to be only 5% bulk Si, both but appears a lower electric field. effect enhanced device design performance investigated.

We report on zinc oxide (ZnO)-based devices produced by a fast, open-air atomic layer deposition (ALD) process relying upon the spatial isolation of reactive gases. At rates greater than 100 Aring per minute, ZnO-based thin-film transistors (S-ALD) show mobility above 15 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Vs and excellent stability. Measurement modeling gas in head is discussed. Saturation curves obtained for aluminum...

The authors report on the fabrication and resultant device characteristics of first 0.25- mu m gate-length field-effect transistor based n-type modulation-doped Si/SiGe. Prepared using ultrahigh vacuum/chemical vapor deposition (UHV/CVD), mobility electron sheet charge density in strained Si channel are 1500 (9500) cm/sup 2//V-s 2.5*10/sup 12/ (1.5*10/sup 12/) -2/ at 300 K (77 K). At 77 K, devices have a current transconductance 325 mA/mm 600 mS/mm, respectively. These values far exceed...

Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly reactors used, film properties, and dopants that have been studied. We highlight how these films are advantageous performance solar cells, organometal halide perovskite light emitting diodes, thin-film transistors. Future technology will enable commercial...

Spatial atomic layer deposition (SALD) is gaining traction in the thin film electronics field because of its ability to produce quality films at a fraction time typically associated with ALD processes. Here, we explore process space for fabrication patterned-by-printing using combination SALD and selective area patterning. First, study growth conditions three primary components our metal oxide electronics, namely alumina (Al2O3) dielectric, zinc (ZnO) semiconductor, aluminum doped ZnO (AZO)...

We report on room-temperature electron transport measurements in modulation-doped strained Si/SiGe heterostructures, grown by ultrahigh-vacuum chemical vapor deposition. A high mobility is expected such samples because of the strain-induced splitting conduction band silicon channel. Record values over 2600 cm2/V s have been measured, almost twice theoretical maximum for relaxed silicon.

Pentacene organic thin-film transistors (TFTs)-driven active matrix light-emitting diode (OLED) displays has been investigated. This letter addresses several process issues unique to this type of display which are important in achieving bright and uniform displays. A bottom contact structure was used fabricate the pentacene TFT backplane. Polyvinyl alcohol parylene were isolate layer passivate The low processing temperature may allow use polymeric substrates lower cost processing. Uniform...

We have observed the fractional quantum Hall effect in magnetotransport properties of a two-dimensional electron gas an n-type Si/SiGe heterostructure. The was for filling factors ν=2/3 and ν=4/3 samples whose mobilities at 1.4 K ranged from 37 000 to 85 cm2/V s.

We have fabricated ring oscillators (ROs) using ZnO thin films deposited by a spatial atomic layer deposition process at atmospheric pressure and low temperature (200degC). Bottom-gate thin-film transistors with aluminum source drain contacts were field-effect mobility of > 15 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V ldr s. Seven-stage ROs operated frequency as high 2.3 MHz for supply voltage 25 V, corresponding to...

We report high-resolution x-ray diffraction measurements of relaxed Si0.7Ge0.3 layers on (001) Si substrates. Strain was relieved either by a glide-limited mechanism in structures where the composition changed abruptly or nucleation-limited having compositionally graded intermediate layer. find that broadening peak surface alloy layer is similar both cases, although threading dislocation densities ranged from 1011 cm−2 to 5×106 cm−2. The effect dislocations widths masked mosaic structure...

Transport of majority carriers across the potential barriers frequently found at grain boundaries in semiconductors is treated by considering sequential drift diffusion and thermionic emission processes. The regimes where or drift-diffusion approximations can reasonably be made are readily determined from analysis. Over a wide doping range, we find boundary transport to under mixed control. Numerical calculations for given barrier height with range bulk levels. A deconvolution scheme...

We describe improvements in both yield and performance for thin-film transistors (TFTs) fabricated by spatial atomic layer deposition (SALD). These are shown to be critical forming high-quality devices using selective area (SAD) as the patterning method. Selective occurs when precursors prevented from reacting with some areas of substrate surface. Controlling individual quality interfaces between layers is essential obtaining good-quality capacitors. The integrity gate insulator particularly...

Glass has excellent electrical and mechanical properties for advanced electronic packaging, even photonics applications. With a large bulk resistance, low moisture sensitivity, dimensional stability, glass wafers have that allow them to be inserted in many of the processes typically used silicon, also advantaged performance some applications, especially those involving high frequency. Thin is required keep latency form-factor contained. In this presentation, we will describe capability...

Atomic layer deposition (ALD) produces conformal films with low defects and a high degree of thickness control. Many applications leverage these properties to yield excellent dielectrics barrier layers. In recent years, ALD has been exploited produce thin-film transistors, in which the technique is capable producing all layers required, including semiconductor. This perspective will examine state-of-the-art use electronics, notably zinc oxide-based transistor. It critical that ZnO-based...

We demonstrate thin-film transistors with the fabrication advantages associated printed electronics and device performance inorganic materials that are typically patterned via photolithography. In this process a polymeric material is to selectively inhibit deposition of electrically active material, which globally applied spatial atomic layer deposition. identify water-soluble inhibitors make attractive choices for printable ink formulations explore interactions two examples space. Using...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Shelby F. Nelson, David H. Levy, Lee W. Tutt, Mitchell Burberry; Cycle time effects on growth transistor characteristics of spatial atomic layer deposition zinc oxide. Journal Vacuum Science Technology A 1 January 2012; 30 (1): 01A154. https://doi.org/10.1116/1.3670878 Download citation file: Ris (Zotero)...

We have investigated the thermal stability of Si/SiGe n-channel heterostructures. To eliminate complication dopant diffusion, we fabricated undoped heterostructure Hall effect devices. With no modulation doping used in our structures, electron concentration strained Si channel is controlled from a back gate. Our devices show high mobility up to 19 500 cm2/V s at 77 K and are stable with negligible reduction after anneals 800 °C for 30 min 950 3 min. These results conform well simulation...