Browsing by Author "Lee, KH"

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A floating well method for exact capacitance-voltage measurement of nano technology
(2003-06-01)
Su, HD
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Chiou, BS
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Wu, SY
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Chang, MH
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Lee, KH
Small gate area with short gate length reduces the C-V distortion of ultrathin oxide devices, but results in high parasitic capacitance/total capacitance ratio. The floating well method can exclude the parasitic capacitance to obtain accurate inversion oxide thickness without using any dummy pattern. It is suitable for nano technology.
Bi-mode breakdown test methodology of ultrathin oxide
(2003-12-01)
Su, HD
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Chiou, BS
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Ko, CY
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Wu, SY
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Chang, MH
The breakdown detections of ultrathin oxide (1.4-2 nm) using a fast voltage ramp have been studied. It was found that the breakdown voltage test of deep sub-micron technology requires the reduction of the gate area of test patterns and therefore the increase of the number of structures due to a large inversion gate current at a low electrical field (> 0. 1 A/cm(2) at 1 V) caused by the scaling down of oxide thickness. The gate current in accumulation mode is smaller than that in inversion mode by more than two orders of magnitude at a low applied voltage (1 V). The bi-mode model proposed in this paper applies a voltage stress in the inversion mode and detects failure in the accumulation mode to enhance the robustness of the breakdown test and reduce the possibility of pseudo breakdown failure. With the proposed method, a shorter test time with an increased test pattern area to improve the efficiency of the breakdown test of ultrathin oxide is achieved.
Characteristics of oxide breakdown and related impact on device of ultrathin (2.2 nm) silicon dioxide
(2003-09-01)
Su, HD
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Chiou, BS
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Wu, SY
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Chang, MH
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Lee, KH
The oxide breakdown characteristics of ultrathin oxide (2.2 nm) have been studied in this paper. Light emission microscopy (EMMI) analysis shows that each breakdown has a specific failure location with a random distribution. Gate leakage current increases for all soft breakdown events are similar. After soft breakdown, the I-V curve still shows the representative direct tunneling characteristics and can be fitted using a dual direct tunneling (DDT) model. Soft breakdown has no effect on the drain current of long-channel devices. Breakdown at the polyedge appears to be of the hard-breakdown mode and results in an abrupt increase in gate current. For short-channel devices, the polyedge is always within the damaged region of an oxide because the channel is shorter than the damaged region of the oxide. Hence, only hard breakdown resulting in permanent damage is observed in short-channel devices.
Novel chip standby current prediction model and ultrathin gate oxide scaling limit
(2002-01-01)
Su, HD
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Chiou, BS
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Lu, PC
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Chang, MH
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Lee, KH
In deep sub-micron technology, leakage current of the oxide layer has a severe impact on chip power consumption due to the scaling down of oxide thickness. The inverter circuit model proposed in this paper provides a simple and quick method of predicting chip standby current. This model takes into account both the conventional device-off current and the inversion gate current, as compared to the conventional approach in which the gate leakage current is small and neglected. The temperature dependence study shows that the logarithm of the device-off current is inversely proportional to temperature. From 25 C, the device-off current increases tenfold for a temperature increase of 50 C, while the inversion gate current is almost temperature independent. Hence, a more aggressive oxide scaling rule could be employed in high-performance products operated at higher temperatures under the same device-off current/inversion gate current ratio.
Vacuum measurement using total-internal-reflection heterodyne interferometry
(1999-10-01)
Chiu, MH
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Lee, JY
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Su, DC
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Lee, KH
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光電工程學系
Based on the effect that the phase difference between s- and p-polarizations at the total-internal-reflection is changed with the variation of the air refractive index, which is related to the air pressure, a new optical method for measuring the air pressure of a vacuum cavity is proposed. From the experimental curve of the phase difference variation measured by the heterodyne interferometry and the calibrated pressure measurement of a vacuum cavity, an empirical formula is derived. With this empirical formula, the mensurable range of this new optical method is 760 to 0.1 torr. (C) 1999 Elsevier Science Inc. All rights reserved.