| 摘要 |
A transistor and method for making the same are disclosed. The transistor is constructed from a collector layer, a base layer, and an emitter layer in a stacked arrangement. The emitter layer is etched to form a mesa on an etched surface, the mesa having a top surface that includes a portion of the emitter layer and an emitter contact and sides joining the top surface with the etched surface. First and second protective layers are then deposited over the emitter contact and etched surface and the portions of these layers that overlie the etched surface are removed. The first protective layer is then preferentially etched thereby undercutting a portion of the first protective layer on the sides of the mesa and creating an overhanging portion of the second protective layer that is utilized to align the deposition of the base contacts.
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