Rapid thermal low-pressure metal-organic chemical vapor deposition (RT-LPMOCVD) of semiconductor, dielectric and metal film onto InP and related materials

Abstract

Abstract Rapidly thermal low-pressure metal-organic chemical vapor deposition (RT-LPMOCVD) was explored as a way to carry out a number of critical steps in the processing of InP-based laser devices, under a vacuum environment. Single-wafer integrated processes (SWIP) employing a multi-chamber cluster tool are suggested as an alternative approach to sequential hybrid batch processing. This work includes demonstrations of the processes for each of the required modules of the cluster. The following processes were realized by means of the RT-LPMOCVD technique: 1. 1. Wafer cleaning using tertiarybutylphosphine (TBP). The InP wafers were annealed at a low protective ambient pressure. Wafer surfaces were degradation-free after being heat-treated at temperatures up to 750 °C for times as long as 30 s under a TBP ambient. 2. 2. III–V semiconductor film deposition. InP and InGaAs layers, undoped and Zn-doped, with low impurity backgrounds were grown using tertiarybutylphosphine (TBP), tertiarybutylarsine (TBA), trimethylindium (TMIn), trimethylgallium (TMGa), and dimethylzinc (DMZn). 3. 3. Deposition of SiO 2 spacer layers onto epitaxially grown InGaAs and InP layers. The SiO 2 films were deposited using a gas mixture of O 2 and 2% diluted SiH 4 in Ar. 4. 4. Reactive ion etching (RIE) of the InP-based material in an electron cyclotron resonance-reactive ion etching (ECR-RIE) chamber. A stainless-steel mask (25 μm thick) with openings (500 μm long and 50–250 μm wide) was aligned on top of the wafer, and RIE of SiO 2 layers was performed through the mask openings. 5. 5. Cleaning of the semiconductor contacting stripes by heating the wafer at 500 °C under a TBP ambient. 6. 6. Metallization of TiN x and W films to produce ohmic contacts and barrier layers. The American Cyanamid tetrakis (dimethylamido) titanium (DMATi) Cypure TM product was used as the TiN x precursor, which was reduced with NH 3 . The W films were deposited using a W 6 source reduced by H 2 .