Thermal stability of Pd/Zn and Pt based contacts to p-In0.53Ga0.47As/InP with various barrier layers

Abstract

Electrical characterization, metallurgical investigation, and thermal stability studies of (Pd, Ti, Au)-based ohmic contacts Pd/Zn/Au contacts to p-In 0.53 Ga 0.47 As/InP with various types of barrier layers to the indiffusion of Au have been examined by Rutherford backscattering spectrometry ͑RBS͒. For the metallizations with a barrier layer of Pd, the aging of the contacts at 400°C for 20 h produced a widespread indiffusion of Au for all thicknesses of the Pd. In comparison, the incorporation of a layer of Pt or amorphous LaB 6 in the contacts prevented an indiffusion of Au and significantly reduced any outdiffusion of the semiconductor elements. The presence of the barrier layer of Pt or LaB 6 produced little or no detrimental increase in c for this contact system. In the as-deposited Pd-based contacts, a layer of Zn in the structure was necessary in order to produce a minimum value of c . After annealing at 500°C, a specific contact resistance in the range 8-10ϫ10 Ϫ6 ⍀ cm 2 was obtained for all of the contacts based on Pd/Zn/Au. A comparison has been made with the characteristics of Pt/Ti/Pt/Au contacts to p-In 0.53 Ga 0.47 As/InP which were shown as stable against the indiffusion of Au.