This work reports on three speed optimized pnp bipolar phototransistors build in a standard 180 nm CMOS process using a special starting wafer. The starting wafer consists of a low doped p epitaxial layer on top of the p substrate. This low doped p epitaxial layer leads to a thick space-charge region between base and collector and thus to a high −3 dB bandwidth at low collector–emitter voltages. For a further increase of the bandwidth the presented phototransistors were designed with small emitter areas resulting in a small base-emitter capacitance. The three presented phototransistors were implemented in sizes of 40 × 40 μm² and 100 × 100 μm². Optical DC and AC measurements at 410 nm, 675 nm and 850 nm were done for phototransistor characterization. Due to the speed optimized design and the layer structure of the phototransistors, bandwidths up to 76.9 MHz and dynamic responsivities up to 2.89 A/W were achieved. Furthermore simulations of the electric field strength and space-charge regions were done.

这项工作报告了三个速度优化的 pnp 双极光电晶体管，使用特殊的起始晶片在标准 180 nm CMOS 工艺中构建。起始晶片由 p 衬底顶部的低掺杂 p 外延层组成。这种低掺杂的 p 外延层导致基极和集电极之间有一个厚的空间电荷区，因此在低集电极 - 发射极电压下具有 -3 dB 的高带宽。为了进一步增加带宽，所提出的光电晶体管被设计为具有小的发射极面积，从而导致小的基极-发射极电容。所展示的三个光电晶体管的尺寸分别为 40 × 40 μm ²和 100 × 100 μm ². 在 410 nm、675 nm 和 850 nm 处进行光学 DC 和 AC 测量以进行光电晶体管表征。由于速度优化设计和光电晶体管的层结构，实现了高达 76.9 MHz 的带宽和高达 2.89 A/W 的动态响应率。此外，还对电场强度和空间电荷区进行了模拟。