No abstract

Gated-MIS tunnel diode with ultrathin oxide has been proposed as a transconductance device. The on/off current ratio of a device is sensitive to oxide thickness. For thicker oxide, the on/off current ratio and transconductance sensitivity are inferior due to the lower oxide tunneling rate. In this work, a technique of utilizing the effective local thinning effect created by positive voltage stress (PVS), which only occurs with the oxide thickness larger than about 3 nm, is demonstrated to improve the on/off current ratio and transconductance sensitivity. After PVS, the on/off current ratio and transconductance sensitivity are strongly enhanced by the creation of an effective local thinning at the edge of the MIS(p) tunnel diode. A transconductance of 8.5 × 10−7 S was found in gated-MIS(p) tunnel diode operated at VTD = 0.5 V and VG ≅ −0.12 V after PVS treatment in contract to that of 1.8 × 10−10 S before PVS.

No abstract

In order to reduce the degradation caused by lateral non-uniformity (LNU) of gate oxides in metal-oxide-semiconductor (MOS) devices, a method to ameliorate the lateral oxide uniformity was proposed. By adopting the anodic oxidation compensation (ANO-compensation) technique to compensate the embedded aluminum layer, significant uniformity improvements were found in capacitance per unit area-voltage (C’-V) and current density-voltage (J-V) characteristics, and the percentage dispersions of capacitance per unit area and current density in accumulation regime also give the support to uniformity improvement. Besides, the outcomes of reliability tests also evidence that the LNU is reduced. Hence, with the advantages of superior oxide uniformity, the enhanced response in inversion capacitance was observed. At last, nitrate solution is used for validating the advantage of anodic oxidation compensation, and the J-V and C-V characteristics show that anodic oxidation compensation is necessary for fabricating reliable MOS-based devices.

The current of metal-insulator-semiconductor (MIS) tunnel diodes is dependent on the Schottky barrier height and there are different mechanisms which dominate MIS tunnel currents while MIS tunnel diodes are biased at positive and negative voltages. In this work, coupled current-voltage behaviors were observed in a MIS(p) tunnel diode with a MOS structure coupled nearby (1). It was found that the MIS(p) saturation tunneling current could be controlled by the voltage bias (V G ) of the nearby MOS capacitor. While V G changes, the minority carrier distribution at the fringe of the MIS tunnel diode also changes. As a result, by wellcontrolling V G , the light to dark current ratio I light /I dark can be effectively enhanced. In this study, two intensities of illumination on MIS(p) tunnel diodes of three different oxide thicknesses were displayed. It is shown that under both intensities of illumination, the light to dark current ratio I light /I dark are all effectively enhanced by well-controlling V G . It is also found that the maxima of current ratio I light /I dark take place at different values of V G for different intensities of illumination. The coupling effect plays an important role in this phenomenon.