Browsing by Author "Chen, IL"

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A design-for-verification technique for functional pattern reduction
(2003-03-01)
Liu, CNJ
;
Chen, IL
;
Jou, JY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This technique reduces the number of required functional patterns by first defining conditions for hard-to-control (HTC) code in a hardware-description-language design and then using an algorithm to detect such code automatically. A second algorithm eliminates these HTC points by selecting a minimum number of nodes for control point insertion.
An efficient design-for-verification technique for HDLs
(2001)
Liu, CNJ
;
Chen, IL
;
Jou, JY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Due to the high complexity of modern circuit designs, verification has become the major bottleneck of the entire design process. There is an emerging need for a practical solution to reduce the verification time. In manufacturing test, a well-known technique, "design-for-testability'', is often used to reduce the testing time. By inserting some extra circuits on the hard-to-test points, the testability can be improved and the testing time can be reduced. In this paper, we apply the similar idea to functional verification and propose an efficient "design-for-verification" (DFV) technique to help users reduce the verification time. The conditions for hard-to-control (HTC) codes in a HDL design are clearly defined, and an efficient algorithm to detect them automatically is proposed. Besides the HTC detection, we also propose an algorithm that can eliminate those HTC points with minimum number of DFV points. By the help of those DFV points, the number of required test patterns to reach the same coverage can be greatly reduced especially for deep-sequential designs.
Effect of annealing on low-threshold-current large-wavelength InGaAs quantum well vertical-cavity laser
(2006-02-01)
Chen, IL
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Hsu, WC
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Kuo, HC
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Sung, CP
;
Chiou, CH
An emission wavelength record emission wavelength of 1245 nm in double InGaAs/GaAs quantum wells without a strain-compensated barrier is obtained by metalorganic chemical vapor deposition (MOCVD). The effect of annealing on highly strained InGaAs quantum wells is analyzed using phtoluminanescence spectra. By comparing devices p-type distributed Bragg reflector (p-DBR) growth temperatures, the preliminary results indicate that a device with a low p-DBR growth temperature of 670 degrees C exhibits a low threshold current and a high light output power. A threshold current of 6.7 mA in an InGaAs vertical-cavity surface emitting laser (VCSEL) in CW operation is realized with an emission spectrum up to 1.26 mu m.
Growth of highly strained RnGaAs quantum wells by metalorganic chemical vapor deposition with application to vertical-cavity surface-emitting laser
(2006-01-01)
Chen, IL
;
Hsu, WC
;
Lee, TD
;
Kuo, HC
;
Su, KH
A series of highly strained InGaAs quantum wells (QWs) with GaAs barriers emitting at wavelength longer than 1.2 mu m are grown on GaAs substrates by metalorganic chemical vapor deposition (MOCVD). The optimized windows of the V/III ratio of the InGaAs layer and the growth rate of the barrier are first investigated on thease highly strained QWs. By an appropriate choice of the growth conditions, we extend the room-temperature photoluminescence (PL) wavelength of InGaAs QWs to 1245 nm, which corresponds to an indium content of 42%. A GaAs-based InGaAs vertical-cavity surface-emitting laser (VCSEL) at an emission wavelength of 1.28 mu m with a large detuning of 90 nm has been realized by the use of highly strained InGaAs QWs.
Low-threshold-current-density, long-wavelength, highly strained InGaAs laser grown by metalorganic chemical vapor deposition
(2005-10-01)
Chen, IL
;
Hsu, WC
;
Kuo, HC
;
Yu, HC
;
Sung, CP
A long-emission-wavelength laser with multiple InGaAs/GaAs quantum wells without a strain-compensated barrier was grown by metalorganic chemical vapor deposition (MOCVD). InGaAs quantum well (QW) broad-area laser diodes with an emission wavelength of up to 1214 nm were realized. A measured room-temperature threshold current density of only 173 A/cm(2) for a 2-mm-cavity device and a transparency current density of 66 A/cm(2) were obtained. The internal quantum efficiency and laser cavity loss were 67% and 6 cm(-1), respectively.