In spite of many years of research, the quantum well intermixing technique has not been able to deliver multibandgap III–V semiconductor wafers at highly attractive costs. We report that UV laser irradiation of InGaAs/InGaAsP/InP quantum well (QW) microstructures in deionized water and rapid thermal annealing (RTA) allows achieving, mask-free, wafers with blueshifted photoluminescence (PL) emission of intensity exceeding almost 10× that of the RTA-only wafers. Our calculations indicate that a ~40 nm thick InOx layer formed on top of the investigated microstructure induces compressive strain in the QW region and leads to this record-high enhanced PL amplitude.
Source:IOPscience
This paper investigated the DC and RF performance of the InP double heterojunction bipolar transistors (DHBTs) transferred to RF CMOS wafer substrate. The measurement results show that the maximum values of the DC current gain of a substrate transferred device had one emitter finger, of 0.8 μm in width and 5 μm in length, are changed unobviously, while the cut-off frequency and the maximum oscillation frequency are decreased from 220 to 171 GHz and from 204 to 154 GHz, respectively. In order to have a detailed insight on the degradation of the RF performance, small-signal models for the InP DHBT before and after substrate transferred are presented and comparably extracted. The extracted results show that the degradation of the RF performance of the device transferred to RF CMOS wafer substrate are mainly caused by the additional introduced substrate parasitics and the increase of the capacitive parasitics induced by the substrate transfer process itself.
Source:IOPscience