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提出了一种新的雪崩光电二极管概念—渠道式APD。用一种新的叉指式p-n结结构,将电子和空穴从存在的空间分开,使其在不同的带隙层内碰撞离化。这样,通过选择适当的带隙差,就能使有效离化率比达到很高(K=α/β>100),从而保持高增益。K值在很大的范围内,这种器件就类似于渠道式光电倍增器,用大多数Ⅲ-Ⅴ族材料制作的晶格匹配的异质结,包括光通信用长波长(1.3≤λ<1.6μm)材料,都可以制作这种结构。本文详细讨论了使用Al_(0.45) Ga_(0.55)As/GaAs,InP/In_(0.53)Ga_(0.475)As和AIAs_(0.92)/GaSb异质结制作的三种渠道式APD的设计。这种结构的另一个重要特点是独特的电容—电压特性,在用作变容二极管时,这一点是很重要的。叉指式结构可以使掺杂浓度高达10~(17)/cm~3的半导体材料大量耗尽,这种新型的半导体器件在FET和集成p-i-n-FET接收器方面也有一些引人注目的用途。它还可以用来研究大电场范围内的高场输送过程(即漂移速度)。
A new avalanche photodiode concept, channel APD, is presented. With a new interdigital p-n junction structure, electrons and holes are separated from the existing space and collide and ionize in different band gap layers. In this way, the effective ionization ratio can be very high (K = α / β> 100) by selecting the appropriate bandgap difference so as to maintain a high gain. K values are within a wide range and the device is similar to a channel photomultiplier, a lattice-matched heterojunction fabricated with most Group III-V materials, including long wavelengths for optical communications (1.3 <λ < 1.6μm) material, can make this structure. In this paper, the design of three channel APDs fabricated using Al_ (0.45) Ga_ (0.55) As / GaAs, InP / In_ (0.53) Ga_ (0.475) As and AIAs_ (0.92) / GaSb heterojunction is discussed in detail. Another important feature of this architecture is the unique capacitance-voltage characteristic that is important when used as a varactor. The interdigital structure can drastically deplete semiconductor materials with doping concentrations as high as 10-17 / cm3. This new type of semiconductor device also has some interesting uses in FETs and integrated p-i-n-FET receivers. It can also be used to study the high-field transport process (ie drift speed) over large electric fields.