Metallurgical Behavior of Gold‐Based Ohmic Contacts to the InP / InGaAsP Material System

Abstract

The performance and reliability of semiconductor devices depend critically on the electrical quality and stability of the metal contacts. Gold‐based metallizations are generally used to form ohmic contacts and Schottky barriers to the III–V material systems. In this paper, we study the interfacial reaction of Be‐Au and Sn‐Au ohmic contact metallizations on ,, and . Staining, cathodoluminescence imaging, and x‐ray microanalysis are used to analyze the metallurgical interactions. Under typical alloying conditions for ohmic contact formation (420°C for 10 min), the depth of metal‐semiconductor interaction is found to depend on the amount of gold deposited. For the same thickness of contact metallization, this depth is largest for , followed by and then . Analysis of LED's shows that the 3 μm thick Sn‐Au n‐contact penetrates ∼3 μm into the window layer. The 2.9 kÅ thick Be‐Au p‐contact completely penetrates the contact layer which is typically 0.5 μm of or .