InP Based, Short Wavelength (3-5um), Quantum Cascade Laser

3-5um emission wavelength's light source is considered to be one of the important atmospheric windows due to the special characteristics.It is always the key research point for science, civilian and defense fields. 4.6um emission wavelength is also the crucial light source for a heat seeking missiles.The special characteristics as a light source, such as the high power, small volume and the wavelength is directly decided by the design of layers thickness of the active region ,make it also be the key research point for the giant military country like USA.The most mature growth semiconductor material is based on InP strain balanced material, and it has been achieved 3W continuous wave room temperature output for 4.6um wavelength. This makes it the crucial light source for variety application.This thesis is mainly based on the analysis of the highly advance active region design methods and the processing and test means of for 3-5um emission wavelength Quantum Cascade Laser.Firstly,the current development of Quantum Cascade Laser is introdecued,and the highly advanced design approach is also analyzed, the further design method also proposed.Sencondly, the processing way was also investigated step by step.The main fabrication means are as followed, PECVD, RIE,ICP, E-beam Evaporation,photolithography, FTIR testing,et,al. The most crucial part among all the processing steps is 10 um depth's dry etching. Study and optimization of room temperature inductively coupled plasma (ICP)-based InP etching using Cl2/Ar/H2 gas mixture for this aim is also developed. The etching depth reaches at least 10um with a smooth surface and a vertical side wall. The study on the compositions of gases, RF power and ICP power on the etching rate has been performed. The highest etching rate obtained is ~3 um/min. For the best recipe, the selectivity ratio over nickel mask is 185:1 which is one of the highest reported so far to our knowledge. For this recipe, the etching rate is 800nm/min and the root-mean-square of the surface roughness is 1.283 nm. The whole etching approach developed here can also be adopted for highly deep etching of other semiconductor materials with ICP systems.