Persons

Евгений Васильевич Кузнецов
Head of the IC’s laboratory, SMC «Technological Center» (Russia, 124498, Moscow, Zelenograd, Shokin sq., 1)

Article author

The metal-induced recrystallization method is an urgent research task for creating the integrated circuits of multi-level architecture, sensitive elements of sensors as well as of the electronic micro- and nanosystems. In the work an optimized method of the metal-induced lateral recrystallization (MILC) of the nano-wire structures from amorphous silicon (a-Si) using nickel silicide has been presented. Based on the given method the nano-wire n-channel field transistors (Gate-All-Around) - MILC GAA transistors have been manufactured. Similar structures have been manufactured based on monocrystal silicon using SOI (SIMOX) structures have been made. The comparison between the electric characteristics of MILS GAA of field nanowire transistors based on recrystallized monocrystal silicon has been performed. It has been shown that the electric-physical characteristics of nano-wire MLC GAA transistors on recrystallized silicon are comparable with nanowire MILC transistors. Thus, the measured MILC G-AA - mobility of electrons in weak fields for MILC GAA of the transistor was 130 cm/V·s for MILC GAA transistor it was 200 cm/V·s.

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A gate dielectric is one of the crucial components of submicron MOS transistor structure which greatly affects its operation reliability. Transistor functionality loss, as well as a failure in the IC operation or a complete failure of the entire IC can be a result of dielectric breakdown. Therefore, the assessment of the gate dielectric defectiveness and its time to failure requires special attention. This paper considers a method for time to failure determination for MOS transistor gate dielectrics based on the time-dependent dielectric breakdown method. The time to failure is determined on the basis of the integral distribution of failures obtained by means of sampling of technological test structures measurements. Various parameter values are used that accelerate failure: high voltage and temperature. The Weibull distribution is used as a failure distribution statistic, and time to failure determination is carried out using a thermomechanical model ( E -model). The research has been performed on test structures represented by MOS capacitors with gate dielectric thickness of 5 nm. The test structures have been developed using the 65 nm technology and placed in a test chip on the same wafer with the integrated circuits. Software has been developed for the research that allows accelerated measurements in automatic mode. As a result of the conducted research, the parameters of the thermomechanical failure model have been determined; the dependencies of the gate dielectric time to failure on the operating conditions have been obtained. It has been found out that both hard and soft dielectric breakdowns can occur for the test structures under study. This method of control can be used to predict the long-term reliability of sub-100 nm MOS transistors gate dielectric, as well as for its production methods assessment.

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The MOS dosimeters are used to keep track of the radiation dose for space, nuclear and medical industries, research laboratories and various applications like portable electronics and etc. MOSFET dosimeters constantly accumulate charge under the ionizing radiation effect, execute direct non-destructive readability of the dose information, have super-small sizes and low power consumption, can operate in a large range of ionizing radiation doses and can be integrated with other sensors and electronics. However, it is impossible to re-use the MOSFET dosimeters for their original purpose. In order to return the threshold voltage to its pre-irradiation value for dosimeter re-use, it is necessary to perform the accumulated charge annealing process. In the work the results of studying the structure of the integral elements, built-in into MOSFET dosimeter for local heating of the gate dielectric for the purpose of annealing the accumulated charge, created under the ionizing radiation, have been shown. The structure of such heating element has been using COMSOL Multiphysics. The heating element is the n -polysilicon gate of the MOSFET, through which electric current is passing. The test structures have been manufactured for 1.2um mixed analog-digital BICMOS technology. The temperature coefficient of resistance for the fabricated samples of the integrated resistors has been measured. It has been determined, that while the electric current passing through the integral element its heating and its resistance change in accordance with temperature coefficient of resistance. A comparison of the simulation results of the temperature dependence on the gate oxide thickness and the current runs through the heating element with the experimentally obtained data has been performed. The proposed method of local heating of the gate dielectric permits to achieve the temperatures of 700 °C order without destructive consequences for the structures and thus, to effectively anneal the accumulated charge in MOSFET dosimeter.

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The promising tool for detecting the intermolecular interactions, including the biochemical interactions, is an ion-sensitive field effect transistor - ISFET. Using the ISFET the recognition of various mechanisms of the specifically adsorbed substances is possible. Also, ISFET is integrated with the CMOS technology, which opens the new perspectives in creation of the intellectual micro and nanosystems. In the work, the influence of the constructive-technological parameters of ISFET on the charge sensitivity has been described using the numerical simulation. The ISFET constructions based on a full depleted structure of silicon on insulator (SOI) with a floating gate have been presented. The constructions differ by the way of forming the contact liquid medium - gate. The analytical dependences of the charge sensitivity of ISFET have been obtained It has been shown that the limiting sensitivity is achievable on a composite structure with extremely small dimensions. The sensitivity of the considered construction of the ISFET-structure, designed by 1.2 µm norms with the analyte adsorbtion was 50 effective charges of electrons. The ISFET, designed with the submicron physical sizes (the wire width is 10 nm and length 100 nm), have sensitivity 1 - 2 electrons.

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