耗尽型 MOS 器件出现较早,但是只是现在才可能实现高速工作。日本日立公司采用了热扩散控制的方法,使耗尽型 MOS 移位寄存器最高能工作在30兆赫。电路中的驱动晶体管采用扩散自对准工艺控制其沟道长度,因此沟道长度仅与两次扩散的深度有关,而与掩模对准的精度完全无关。沟道长度类似于双报晶体管的基区宽 Depletion MOS devices appear earlier, but it is only now possible to achieve high-speed work. Hitachi, Japan, adopted a thermal diffusion-controlled approach that allows depletion-mode MOS shift registers to operate at up to 30 MHz. The drive transistor in the circuit uses a diffusion self-aligning process to control its channel length, so the channel length is only related to the depth of two passes, regardless of the accuracy of the mask alignment. The channel length is similar to the base width of a double-pin transistor