Ultrafast Avalanche Photodiode and Manufacturing Method

摘要

The present invention relates to an ultra-fast avalanche photodiode and a method of manufacturing the same, wherein the semiconductor substrate of InP is doped with a high concentration of impurities of a first conductivity type, and the carrier concentration is 1 to 5 x 10 ¹⁵ cm ^-3 on top of the semiconductor substrate. Crystal-grown first conductive photoconductive layer of InGaAs and a first conductive layer composed of one or more layers on top of the light absorbing layer, lattice matched with InP, and crystal-grown with a carrier concentration of 1 to 5 × 10 ¹⁵ cm ^-3 . A grading layer of type InGaAsP, a charge layer of the first conductive type InP crystal-grown on top of the grading layer to be adjusted to a thickness x carrier concentration of 2.5 to 3.5 x 10 ¹² cm ^-2 , and a carrier on top of the charge layer An amplification layer of the first conductive type InP crystal-grown at a concentration of 1 to 5 x 10 ¹⁵ cm ^-3 , and a second conductive type formed by two diffusions in a predetermined portion of the amplification layer One time between the second guard ring and the second guard ring Diffusion of the second conductive impurity by the acid to be bonded between the first guard ring of InP formed by doping at a high concentration so as to have a diffusion depth shallower than that of the second guard ring, and the first guard ring. The second conductive type is an active region of InP formed by doping at a high concentration so that the impurity of the second conductivity type has the same diffusion depth as that of the second guard ring, and the second conductive type is formed in contact with the upper portion of the active region on the amplification layer. An electrode, a surface protective layer formed on the amplification layer other than the active region, an antireflection film formed on the lower surface of the semiconductor substrate so as to correspond to the second conductive electrode, and an antireflection film on the lower surface of the semiconductor substrate; The nonconductive portion includes the first conductive electrode.;Accordingly, since the diffusion depth of the second guard ring is deeper than that of the first guard ring, the electric field strength of the corner portion of the active region is relatively low, so that the effective guard ring is possible, and the depth of the second guard ring is also increased. It can be adjusted with the depth of, so the process is very easy and the depth can be easily adjusted. And, since only one second guard ring is formed, the area of the diode can be reduced, and thus the capacitance of the diode can be reduced, and the width of the amplification layer is 0.2. Since it can be -0.3 micrometers, the gain-bandwidth product can be increased to 100 GHZ or more.