Selective Wet Etching Process for Ni-InGaAs Contact Formation in InGaAs N-MOSFETs with Self-Aligned Source and Drain

Abstract

Etch rates of Ni-InGaAs metallic film and Ni in HCl, HNO3, HF and SPM etch chemistries were determined using sheet resistance method, step height measurements, and cross sectional TEM characterization. HCl and HNO3 based chemistries were studied in detail. The etch selectivity of Ni over Ni-InGaAs in various etchants was studied. Concentrated HCl was found to have the highest selectivity of approximately 15.6. HNO3 (1:10) and HNO3 (1:20) solutions provides good selectivities of 4.3 and 4.5 respectively. The results of this work could be useful for the formation of Ni-InGaAs self-aligned source and drain in InGaAs N-MOSFETs.