What of the correct sequence of the following step in the fabrication of a monolithic, bipolar junction transistor?
1. Emitter diffusion
2. Base diffusion
3. Buried layer formation
4. Epi-layer formation1
3, 4, 1, 2
2
4, 3, 1, 2
3
3, 4, 2, 1
4
4, 3, 2, 1