Methods for dry etching semiconductor devices
| DWPI Title: Method for etching semiconductor device for use in communication device, involves introducing supplementary gas into plasma reactor for supplemental period, where supplementary gas comprises boron trichloride |
| Abstract: The present invention provides methods for etching semiconductor devices, such aluminum nitride resonators. The methods herein allow for devices having improved etch profiles, such that nearly vertical sidewalls can be obtained. In some examples, the method employs a dry etch step with a primary etchant gas that omits BCl3, a common additive. |
| Use: Method for etching a semiconductor device for use in a communication device. Uses include but are not limited to a resonators, a filter e.g. band select filter, a filter bank, a oscillator, a photonic device, an LED, a photonic crystal, a vertical cavity surface emitting laser, a reflectance modulator, and a photonic circuit. |
| Advantage: The method enables forming AlN resonators with vertical sidewalls to reduce spurious modes and improve a quality factor of the resonator, both of which are key figures of merit for resonators. The method enables performing plasma etch process to pattern the hard mask with trench patterns including vertical sidewalls, thus eliminating a possibility of transferring sidewall slope from the hard mask to the semiconductor material to be etched. The method enables providing a high etch rate selectivity, in which the hard mask is etched at a higher rate while minimizing the etch rate of the semiconductor material. The method enables optimizing the resonator to promote symmetric modes, asymmetric modes, and/or shear modes of an acoustic wave propagating in a piezoelectric crystal. |
| Novelty: The method (100) involves etching an exposed semiconductor material located in proximity to a trench pattern (135) by introducing primary etchant gas into a plasma reactor for a primary etching period, where the primary etchant gas comprises chlorine and does not include boron trichloride for providing an etched semiconductor (162). Second supplementary gas is introduced into the plasma reactor for second supplemental period, where the second supplementary gas comprises boron trichloride and duration of the second supplemental period is less than duration of the primary etching period. |
| Filed: 6/2/2015 |
| Application Number: US14728810A |
| Tech ID: SD 13053.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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