Drain-Engineered Reconfigurable Transistor Exhibiting Complementary Operation

In this paper, we propose and simulate a multifunctional transistor that exhibits device reconfigurability and realizes both nFET and pFET electrical characteristics when adequately biased. The use of this device will significantly reduce the transistor count in realizing sequential and combinational circuits and will result in highly compact design. The device uses a dual fin structure having a single mid-gap workfunction gate (∼4.65 eV) alongside dual metal (metal-silicide) drain regions. It employs n + / p + - i junctions at the source-channel interface along with the Schottky junctions at the channel-drain interface. In practice, metal-silicides such as erbium/ytterbium silicide (ErSi x /YbSi x ) for the n -drain and platinum silicide (PtSi) for the p -drain can be used as they provide smallest electron and hole Schottkybarrier heights (SBHs). Simulations carried out using calibrated parameters show better drive current (≈ 10 −2 −10 −3 A/ µ m) compared to the quantum tunneling current in simulated stateof-the-art multifunctional devices (≈ 10 −4 − 10 −5 A/ µ m). In addition, butterfly curves show symmetric high (NM H ) and low (NM L ) noise margins of 0.43V and 0.29V for zero and finite SBHs, respectively. The switching characteristics is shown to have an overshoot of ∼0.15 V for realistic SBHs which is then eliminated for the case of zero SBHs. In the last section, it is also demonstrated that a simplified structure having single mid-gap workfunction (∼4.65 eV) drain of Nickel silicide (NiSi) does not hamper the reconfigurability of the device. Index Terms —MOSFET, Multifunctional circuit, CMOS, Schottky junction.

Reduced Operation Current of Oxygen-Doped ZrN Based Resistive Switching Memory Devices Fabricated by the Radio Frequency Sputtering Method

In this work, we report the feasibility of resistive switching (RS) properties of oxygen-doped zirconium nitride (O-doped ZrN) films with platinum (Pt) and platinum silicide (PtSi) bottom electrode (BE), produced by a sputtering method. Compared to O-doped ZrN using Pt BE, when Pt/p-Si was used as BE, the foaming voltage slightly increased, but the operation current was reduced by about two orders. In particular, the average reset current of the O-doped ZrN memory cells was reduced to 50 µA, which can delay deterioration of the element, and reduces power consumption. Therefore, the use of PtSi as the BE of the O-doped ZrN films is considered highly effective in improving reliability through reduction of operating current of the memory cells.

Structural-phase junctions in the system of Pt–Si during rapid thermal treatment

In recent years the interest to silicides significantly rose relating to their huge potentialities as the material of the low-Ohm contacts and interconnections of metallization of the silicon integrated circuits. In view of this the necessity appeared to consider more extensively the thermal dynamic, electric and structural peculiarities of their formation. Purpose of the work was in investigation of influence of the rapid thermal treatment on the structural –phase junctions in the system of Pt–Si during formation of platinum silicide. As samples, the Pt films were used, 43.7 nm thick and applied on the substrates of the mono-crystal silicon KEF КЭФ 0.5 with orientation (111) by means of the magnetron sputtering of the platinum target with purity of 99.95 % on the unit MRS 603 with the cryogenic pumping to the pressure not worse, than 5 · 10–5 Pa. As the operating medium, argon was used, whose purity constituted 99.933 %. Rapid thermal treatment was performed in the nitrogen medium within the temperature range from 200 to 550 °С with a step of 50 °С and the time period of 7 s. The process of interaction of platinum with silicon during treatment of the Pt–Si system was evaluated by means of the analysis of the RBS spectra. It is demonstrated, that within the temperature range of 200 °С ≤ Т ≤ 300 °С during 7 s of the rapid thermal process on the boundary of the metal film with the substrate, formation takes place of the Pt2Si layer owing to diffusion of the Pt atoms into silicon via the layer of the growing silicide. The temperature Т = 300 °С is peculiar for the complete application of the Pt film during 7 s in process of the silicide formation of the single phase system of Pt2Si. At 350 °С ≤ Т < 450 °С formation is registered of the double phase system of Pt2Si → PtSi, starting from the inter-phase boundary of Si/Pt2Si predominantly owing to the opposite diffusion of the Si atoms into the layer of Pt2Si. The temperature of the rapid thermal treatment Т = 450 °С marks formation of the thermally stable balanced structure of PtSi along the entire silicide thickness, which is 50–100 °С lower and considerably more rapid, than during the long-term balanced thermal treatment.

INFLUENCE OF TIME MODES OF THERMAL TREATMENT ON Pt-Si SYSTEM MICROSTRUCTURE

The paper is purposed to establish the principles of the micro-structural changes of Pt-Si system during the rapid thermal treatment. The Pt films 43.7 nm thick were applied on the substrates of mono-crystal silicon KEF 0.5 with orientation (111) by means of the magnetron platinum target sputtering (purity of 99.95 %) on the unit MPC 603 with the cryogen pumping to the pressure of no less than 5∙10-5 Pa. Argon was used as a working medium, whose purity constituted 99.933 %. Rapid thermal treatment was performed in the mode of the thermal balance with irradiation of the reverse side of the wafer by means of the non-coherent light flow in the nitrogen medium within the temperature range from 200 to 550 °C with a step of 50 °С during 7 s. In parallel, the solid phase synthesis was performed of platinum silicide by means of the standard method with application of the continuous single stage thermal treatment in the analogue medium (T = 550 °C, t = 30 min). Temperature monitoring was performed by means of the thermal couple method with accuracy of ±0.5 °C. The grain size was determined by the translucent electron microscopy method. Thickness of platinum silicide under formation, its surface micro-relief and the separation boundaries with silicon were determined by means of the raster electron microscopy. It is demonstrated, that with the rise of the rapid thermal treatment one can observe growth of the platinum film on silicon. A comparative analysis was conducted of the average size of grains, micro-relief of the PtSi surface and its separation boundary with silicon for two methods of its formation with application of the rapid thermal treatment and with application of the traditional continuous thermal treatment at the temperature of 550 °C during 30 min in the nitrogen atmosphere. By means of the raster electron microscopy method it is demonstrated, that size of the micro-relief on the separation boundary of PtSi-Si does not exceed 15.9 nm and the size of grains is 37.7 nm. This is in 2.5 and 3.1 times smaller, then in the case of the traditional single stage continuous thermal treatment.