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The intrinsic response of quantum dash lasers are measured using a pulse optical modulation technique. Our results show fast well-to-dash carrier capture and intra-dash carrier relaxation with K-factors independent on the pump wavelengths.

We demonstrate bandgap tuned InAs/InAlGaAs quantum-dash-in-well lasers grown on InP material using postgrowth quantum heterostructure intermixing. Compared to the control (non-intermixed) lasers, the light-current characteristics of lasers with emission wavelength tuned by over 100 nm shows insignificant changed suggesting that the quality of the intermixed material is well-preserved.

Three LOCOS-type isolations, viz. modified Scaled LOCOS (MSL), Sidewall Sealed MSL (SSMSL), and Recessed SSMSL (RSSMSL) are evaluated for the 0.6 /spl mu/m-pitch isolation of 256 Mbit DRAM. About 4000 /spl Aring/ field oxide grown in a 1100/spl deg/C wet ambient is found to be optimal for field oxide thinning and bird's beak "punch-through" effects. At a given pad oxide thickness of 100 /spl Aring/ the end-of-line encroachment is the largest for MSL isolation, which essentially rules out MSL as a possible candidate. Although both SSMSL and RSSMSL have similarly good isolation characteristics and diode leakages, only RSSMSL has the undesirable subthreshold double-hump effect and reduced gate oxide integrity, both of which are due to the sharp corners associated with the silicon recess etch of the RSSMSL structure. Therefore, for the three structure studied, only SSMSL is a viable candidate for the 0.6 /spl mu/m-pitch isolation of 256 Mbit DRAM.