OHMIC CONTACTS FOR COMPOUND SEMICONDUCTORS

Although there has been strong demand for low -resistance, highly reli able Ohmic contacts for compound semiconductors to realize high-freque ncy transistors, high-power devices, and light-emitting (LED) and lase r diodes (LD), development of the Ohmic contact technologies has been made on a trial-and-error basis. The primary reason is lack of fundame ntal data to design ideal metal/semiconductor interfaces due to comple xity of elements involved at the interfacial reaction. In this article , we review recent systematic studies carried out for Ohmic contact ma terials to n-GaAs and then address critical issues to apply the method ology established in nGaAs to develop low-resistance Ohmic contacts fo r p-ZnSe and p-GaN, which are desperate for blue-green LED and LD.