Effect of strained interfacial layer and large misorientation on SQW, 2DEG, and multisteps in InGaP/(In)GaAs heterostructures grown by MOVPE

We studied 2DEG performance in Si-doped (including heavily planar-doped) InGaP/GaAs heterostructures. We found that Si diffused from InGaP to GaAs, and an In/sub 0.3/Ga/sub 0.7/P (not GaP) interfacial layer between the Si-doped layer and the channel layer is optimum for high 2DEG performance. Step bunching due to misorientation is an interesting issue in MOVPE. We studied a misorientation effect and found that large misorientation over 10/spl deg/ from [001] improves the SQW quality without inserting a GaP layer at the interface. We also found that the performance of InGaP-based HEMTs (including inverted-type) is not linked with the SQW quality, and that misorientation towards <111>A is required for high mobility. We characterized multisteps using atomic force microscopy (AFM) and concluded that the multistep configuration mainly affects abruptness in device structures.