Semiconductor circuit made by two-stage planar diffusion process - uses mfg. process with specified masking and etching of oxide layers

摘要

The semiconductor is made by a two-stage planar diffusion process. A first diffusion window (3) is created in the masking layer (1) for the first stage of diffusion. During the first stage the semiconductor surface exposed in the window is oxidised to form an oxide layer (6). A second oxide layer (18) of the same thickness is formed on the other side (5) of the semiconductor. A second mask (11) is then applied and has second windows. The structure is then etched until the second oxide layer is removed and the mask (9) thickness is equal to the thickness of the masking layer (1) less the oxide.