Optical modulators operating at near-infrared wavelengths are of interest for a variety of applications including bi-directional communications and optical interconnects. The fabrication of 1.06 pm and 1.32 pm operating wavelength strained-layer-superlattice vertical-cavity optoelectronic modulators requires the formation of a p-type ohmic contact to the InA1AslInGaAs quarter-wave bottom mirror stack. In this study, BeAu and TiPtAu p-type ohmic contact metallization schemes were evaluated for use on molecular beam epitaxy (MBE) grown In,,,Al,,~/In,,,Ga~,,As and 1n.,,Al,~,A~/In.~,Ga.~~As device heterostructures. Recessed and nonrecessed transmission line measurement (TLM) structures were fabricated and evaluated as a . function of rapid thermal anneal (RTA) temperatures over the range of 360" C -420" C . Atomic force microscopy (AFM) was used to determine the surface morphology of each sample for evidence of metal or material degradation. For contacts directly on InGaAs layers, TiPtAu contacts had relatively high specific contact resistance values of p, -3 x Qcm2 and displayed no dependance on the anneal. The BeAu contacts had minimum specific contact resistance values of p, -5 x lo-' Qcm' but showed evidence of degradation at higher temperatures. Contacts directly made to InAlAs layers had minimum specific contact resistances of p, -4 x lo-' Qcm2 and were improved slightly with the addition of a thin GaAs layer. DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recornmendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.Portions of this document may be illegible in electronic image products. Images are produced from the best available 0 - These devices require the growth of relatively thick (In,M,Ga)As buffer layers on GaAs substrates to provide an appropriate lattice constant for subsequent growth of the active device structure.Low-doped ternary InAlAsLInGaAs multilayers with precisely controlled compositional values and thicknesses are then grown to create the quarter-wave mirror stacks and cavity region which provide reflectance or transmission mode operation at the desired wavelength. The highest quality material with minimization of dislocations and cross-hatching is achieved by using molecular beam epitaxy (MBE) at low temperatures (-400' C) [4]....