Browsing by Author "Luo, JJ"

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A new CMOS readout circuit for uncooled bolometric infrared focal plane arrays
(2000)
Yu, TH
;
Wu, CY
;
Chin, YC
;
Chen, PY
;
Chi, FW
By incorporating the basic Constant Current (CC) configuration with the buffered direct injection (BDI) structure, a new readout circuit called the constant current buffered direct injection (CCBDI) is proposed for the uncooled bolometer detector FPAs. Due to the use of BDI structure, the offset is decreased and the linearity range is increase. Thus linearity, dynamic range, and uniformity are improved. An experimental chip of 64x64 CCBDI FPA readout circuit has be designed and fabricated by using 0.5 mu m double-poly double-metal n-well CMOS technology with the cell size of 50x50 mu m(2). The measured linearity is 94.36% whereas the measured uniformity is 81.3%. Both measurement and simulation results have verified the advantageous features of the proposed CCBDI readout circuit. It is believed that the new CCBDI structure has a great potential in the applications of large uncooled bolometer FPAs.
Fabrication of cantilever type microswitches using surface micromachining technology
(2000)
Chang, KM
;
Jou, CF
;
Luo, JJ
;
Kuo, LY
;
Deng, IC
Cantilever type microswitches have advantages of low electrostatic actuation voltage and high isolation in RF applications. Of particularly importance, it can be integrated with microstrip line in series or shunt connection mode for building the RF circuit or system directly. Figure 1(a) is an idea switch with single pole, single throw configuration (SPST). As shown in figure 1(b). the microswitch in our study is similar in structure to an ideal switch. Suspended aluminum membrane with perforation holes is used as a movable electrode that will form the resistive contact with the bottom electrode underneath at the free end through electrostatic actuation process. The fabrication processes will be described as shown in figure 2 for constructing the 4 um gap structure of microswitches. Figure 3 shows the structure of microswitch using field emission scanning electron microscope (FESEM). The bending of the membrane was resulted from the thermal histogram of lithography and dry release process in reactive ion etching system, which can be controlled by process parameters optimization. Hysteresis measurement on HP-4156 as shown in figure 4 has demonstrated the operation of microswitch. The actuation voltage shows higher value than expected from simulation due to the existence of residual stress. However, the small curvature of this cantilever type membrane indicates the feasibility of building the application circuit from this low stress membrane microswitches.
Leakage performance and breakdown mechanism of silicon-rich oxide and fluorinated oxide prepared by electron cyclotron resonance chemical vapor deposition
(1997-05-01)
Chang, KM
;
Wang, SW
;
Yeh, TH
;
Li, CH
;
Luo, JJ
The characteristics of silicon-rich oxide and fluorinated oxide (FxSiOy) films deposited in an electron cyclotron resonance chemical vapor deposition system with SiH4 and O-2 as the oxide sources and CF4 as the fluorinating precursor are investigated in this work. According to experimental results, the dangling bonds in Si-rich oxide behave as positively by charged electron traps and degrade the dielectric strength by lowering the barrier height for Fowler-Nordheim tunneling. On the other hand, a small amount of incorporated F atoms will passivate and neutralize these excess Si dangling bonds, thereby elevating the dielectric strength. However, too much incorporated F will degrade the pretunneling leakage performance owing to the porosity and fatigues structure in FxSiOy film. The high leakage and even breakdown at low field strongly limits the incorporated F concentration in FxSiOy film and the lowering of dielectric constant.
Wet etching characterization of InSb for thermal imaging applications
(2006-03-01)
Chang, KM
;
Luo, JJ
;
Chiang, CD
;
Liu, KC
;
電子工程學系及電子研究所
A citric acid/hydrogen peroxide-based chemical system has been reported for the first time to meet the requirements of continuously scaling down the pixel area for InSb high-density infrared camera applications. This chemical system with a reaction-rate-limited mechanism was concluded to have superior etching performance compared with the nitric acid-based Solution. It is established that this etching mechanism has better control over device structure uniformity due to its linear proportionality to etching time and its nondependence oil agitation and exposed etched area. Two different chemical systems have been studied to form the high-density mesa structures ill this Study. The wet etching characteristics corresponding to these chemical Solutions were measured and analyzed. From atomic force microscopy (AFM), the results clearly indicate that the surface-reaction-rate-limited dominant-control mechanism for InSb mesa etching in citric acid/hydrogen peroxide produces a fairly smooth morphology near junction edges and well-controlled sidewall profiles. Good step coverage for dielectric deposition as shown by field-emission scanning electron microscopy and a highly uniformly distributed dark current of InSb pn junction arrays at 77 K have proven the feasibility of the citric acid/hydrogen pet-oxide wet etching process to bring superior etching performance compared with the nitric acid-based Solution.