Semi-planar avalanche photodiode
An avalanche photodetector is disclosed. An apparatus according to aspects of the present invention includes a mesa structure defined in a first type of semiconductor. The first type of semiconductor material includes an absorption region optically coupled to receive and absorb an optical beam. The apparatus also includes a planar region proximate to and separate from the mesa structure and defined in a second type of semiconductor material. The planar region includes a multiplication region including a p doped region adjoining an n doped region to create a high electric field in the multiplication region. The high electric field is to multiply charge carriers photo-generated in response to the absorption of the optical beam received in the mesa structure.
1. An apparatus, comprising:
a mesa structure defined in a first type of semiconductor, the first type of semiconductor material including an absorption region optically coupled to receive and absorb an optical beam; and
a planar region proximate to and separate from the mesa structure and defined in a second type of semiconductor material, the planar region including a multiplication region including a p doped region adjoining an n doped region to create a high electric field in the multiplication region to multiply charge carriers photo-generated in response to the absorption of the optical beam received in the mesa structure,
wherein the planar region further includes a guard ring structure disposed in the second type of semiconductor material of the planar region surrounding the mesa structure,
wherein the guard ring structure is a floating guard ring at an interface between the absorption region and the multiplication region.
2. The apparatus of claim 1 wherein the first type of semiconductor comprises germanium and the second type of semiconductor material comprises silicon.
3. The apparatus of claim 1 wherein the first type of semiconductor comprises InGaAs and the second type of semiconductor material comprises silicon.
4. The apparatus of claim 1 wherein the guard ring structure is a floating guard ring including p doped second type of semiconductor material.
5. The apparatus of claim 1 further comprising contacts coupled to the mesa structure and planar regions, respectively, to receive an external bias voltage to create a low electric field in the mesa structure.
6. The apparatus of claim 5 further comprising a p doped region in the mesa structure and a second n doped region in the planar region coupled to the contacts.