Dae-Hyung Cho

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We report a low phase noise transformer-coupled CMOS VCO using a bias-level shifting technique. Two fully integrated voltage-controlled oscillators (VCOs) are presented as a proof of concept. A conventional LC VCO with a current source achieves a phase noise of -116.67 dBc/Hz at 1 MHz offset from the 5.6 GHz center frequency, taking 3.9 mA from a 1.5 V(More)
We selected a sputtered-Zn(O,S) film as a buffer material and fabricated a Cu(In,Ga)Se2 (CIGS) solar cell for use in monolithic tandem solar cells. A thermally stable buffer layer was required because it should withstand heat treatment during processing of top cell. Postannealing treatment was performed on a CIGS solar cell in vacuum at temperatures from(More)
This paper presents the measurement and characterization of multilayered interconnect capacitances for a 0.35m CMOS logic technology, which become a critical circuit limitation to high performance VLSI design. To measure multilayered capacitances of nonstacked, stacked, and orthogonally crossing interconnect lines, new test structures and measurement method(More)
We fabricated Cu(In,Ga)Se2 (CIGS) solar cells with chemical-bath deposited (CBD) ZnS buffer layers with different deposition times. The conversion efficiency and the fill factor of the CIGS solar cells reveal a strong dependence on the deposition time of CBD-ZnS films. In order to understand the detailed relationship between the heterojunction structure and(More)
We fabricated Cu(In,Ga)Se2 (CIGS) solar cells with a chemical bath deposition (CBD)-ZnS buffer layer grown with varying ammonia concentrations in aqueous solution. The solar cell performance was degraded with increasing ammonia concentration, due to actively dissolved Zn atoms during CBD-ZnS precipitation. These formed interfacial defect states, such as(More)
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