US 5,844,291 AGranted

Wide wavelength range high efficiency avalanche light detector with negative feedback

AssigneeBoard of Regents, The University of Texas System

InventorsPeter P. Antich, Edward N. Tsyganov

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Abstract

A novel use of a solid state light detector with a low impedance substrate is described. Light that enters the substrate after traversing the antireflective layer creates an electron-hole pair. The electrons are collected in a crystalline epitaxial layer that spans the space charge region, or depletion layer. A high electric field accelerates free electrons inside the depletion region. The electrons collide with the lattice to free more holes and electrons resulting from the presence of a n-p junction, or diode. The diode is formed by placing the crystalline layer which has positive doping in close proximity with the electrodes which have negative doping. The continual generation of charge carriers results in avalanche multiplication with a large multiplication coefficient. During the avalanche process, electrons can be collected enabling light detection. A resistive layer is used to quench, or stop, the avalanche process.

Claims15

Dependent claims

A solid-state light detector comprising:

a) a low impedance silicon semiconductor substrate having an upper and a lower surface;
b) a first heavily doped conductive layer having a top surface and a bottom surface and a first and a second end, wherein the top surface is in contact with the lower surface of the substrate;
c) a silicon carbide resistive layer on top of the upper surface of the substrate;
d) a silicon dioxide isolating layer on top of the resistive layer;
e) a crystalline epitaxial layer of p-type semiconductor material on top of the isolating layer;
f) a plurality of semi-cylindrical n.sup.+ regions inside the epitaxial layer having dimensions and spacing that are selected to produce a high electric field;
g) a second heavily doped conductive layer having a top surface and a bottom surface and a first and second end, wherein said bottom surface is in contact with the epitaxial layer;
h) an antireflective coating in contact with the top surface of the second heavily doped conductive layer;
and
i) a pair of electrical contacts respectively connected to the first end of the first heavily doped conductive layer and the first end of the second heavily doped conductive layer.

7 more elements

Dependencies are inferred from the claim text.