Browsing by Author "Chang, T"

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Microstructure effects on quantum efficiency in PtSi/p-Si(100) Schottky barrier detector
(2001-02-15)
Horng, GJ
;
Chang, CY
;
Chang, T
;
Ho, C
;
Wu, CS
The microstructure effects on the performance of the PtSi Schottky barrier detector (SBD) have been investigated in detail. The growth temperatures were ranged from 350 to 550 degreesC. The thickness of the PtSi film measured by high resolution transmission electron microscopy (HRTEM) is around 4 nm. The electron diffraction pattern shows an intermingling of both (1 (1) over bar 0) and (I (2) over bar 1) orientations when the PtSi film is formed at 350 degreesC. However, the diffraction patterns show only (1 (2) over bar1) orientation when the PtSi films are formed above 450 degreesC. It was found that the electrical barrier height of the Schottky barrier detector formed at 350 degreesC is about 0.02 eV higher than that formed above 450 degreesC. The microstructure of the PtSi film does not change even though the formation temperature is further increased to 550 degreesC. Nevertheless, the higher the formation temperature, the larger is the grain size. It was also observed that the grain size does not change the electrical barrier height. However, the quantum efficiency of the detector is much higher if the grain size is larger. The results indicate that the quantum efficiency of the detector can be improved if the PtSi film has (1 2 1) orientation and larger grain size. (C) 2001 Elsevier Science B.V. All rights reserved.
Thin oxides with in situ native oxide removal
(1997-09-01)
Chin, A
;
Chen, WJ
;
Chang, T
;
Kao, RH
;
Lin, BC
We have studied the inversion layer mobility of n-MOSFET's with thin-gate oxide of 20 to 70 Angstrom. Direct relationship of electron mobility to oxide/channel interface roughness was obtained from measured mobility of MOSFET's and high-resolution TEM. By using a low-pressure oxidation process with native oxide removed in situ prior to oxidation, atomically smooth interface of oxide/channel was observed by high-resolution TEM for oxide thicknesses of 11 and 38 Angstrom. The roughness increased to one to two monolayers of Si in a 55-Angstrom oxide. Significant mobility improvement was obtained from these oxides with smoother interface than that from conventional furnace oxidation. Mobility reduction with decreasing oxide thickness was observed in the 20- and 35-Angstrom oxide, with the same atomically smooth oxide/channel interface. This may be due to the remote Coulomb scattering from gate electrode or the gate field variation from poly-gate/oxide interface roughness.
Thin oxides with in situ native oxide removal
(1997-09-01)
Chin, A
;
Chen, WJ
;
Chang, T
;
Kao, RH
;
Lin, BC
We have studied the inversion layer mobility of n-MOSFET's with thin-gate oxide of 20 to 70 Angstrom. Direct relationship of electron mobility to oxide/channel interface roughness was obtained from measured mobility of MOSFET's and high-resolution TEM. By using a low-pressure oxidation process with native oxide removed in situ prior to oxidation, atomically smooth interface of oxide/channel was observed by high-resolution TEM for oxide thicknesses of 11 and 38 Angstrom. The roughness increased to one to two monolayers of Si in a 55-Angstrom oxide. Significant mobility improvement was obtained from these oxides with smoother interface than that from conventional furnace oxidation. Mobility reduction with decreasing oxide thickness was observed in the 20- and 35-Angstrom oxide, with the same atomically smooth oxide/channel interface. This may be due to the remote Coulomb scattering from gate electrode or the gate field variation from poly-gate/oxide interface roughness.
Ultra-thin oxide with atomically smooth interfaces
(1995)
Chin, A
;
Chen, WJ
;
Kao, RH
;
Lin, BC
;
Chang, T
Native oxide is an important issue for ultra-thin oxide, which is strongly related to the gate oxide integrity such as Q(BD), interface scattering, etc. We have designed a leak-tight low-pressure oxidation system to desorb the native oxide in-situ. Atomically flat interfaces between oxide and Si are obtained for oxide thicknesses of 11 and 38 Angstrom. Because of the smooth interface and good thickness uniformity of oxide, both high-field electron mobility and oxide breakdown behavior are much improved.