Ge/Si avalanche photodiode with integrated heater and fabrication method thereof

• US 9,583,664 B2
• Filed: 02/03/2016
• Issued: 02/28/2017
• Est. Priority Date: 02/21/2014
• Status: Active Grant

• Current Assignee: SiFotonics Technologies Co., Ltd.
• Original Assignee: SiFotonics Technologies Co., Ltd.
• Inventors: Shi, Tuo, Cai, Pengfei, Wang, Liangbo, Zhang, Nai, Chen, Wang, Li, Su, Hong, Ching-yin, Huang, Mengyuan, Pan, Dong
• Primary Examiner(s): Vu, David
• Assistant Examiner(s): Nguyen, Cuong B
• Application Number:
  US15/014,331
• Publication Number:
  US 20160155883A1
• Time in Patent Office: 391 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 27/14 including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation radiation-sensitive components structurally associated with one or more electric light sources only H01L31/14; couplings of light guides with optoelectronic elements G02B6/42
• CPC Class Codes: H01L 31/02027 for devices working in avalanche mode
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H01L 31/024 Arrangements for cooling, heating, ventilating or temperature compensation for photovoltaic devices H01L31/052
• CPC Class Codes: H01L 31/028 including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/1075 in which the active layers, e.g. absorption or multiplication layers, form an heterostructure, e.g. SAM structure
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Various embodiments of a novel structure of a Ge/Si avalanche photodiode with an integrated heater, as well as a fabrication method thereof, are provided. In one aspect, a doped region is formed either on the top silicon layer or the silicon substrate layer to function as a resistor. When the environmental temperature decreases to a certain point, a temperature control loop will be automatically triggered and a proper bias is applied along the heater, thus the temperature of the junction region of a Ge/Si avalanche photodiode is kept within an optimized range to maintain high sensitivity of the avalanche photodiode and low bit-error rate level.

Claims

1. An apparatus, comprising:

a substrate;

at least one top-illuminated Ge/Si avalanche photodiode on a primary side of the substrate, the Ge/Si avalanche photodiode comprising;

a first Si layer doped with dopants of a first type;

a second Si layer as a multiplication layer which is un-intentionally doped, lightly doped with dopants of the first type at a concentration of less than 5E17 cm<sup>−

3</sup>, or lightly doped with dopants of a second type at a concentration of less than 5E17 cm<sup>−

3</sup>;

a charge layer doped with dopants of the second type;

a Ge layer as an absorption layer which is un-intentionally doped, lightly doped with dopants of the first type at a concentration of less than 5E17 cm<sup>−

3</sup>, or lightly doped with dopants of the second type at a concentration of less than 5E17 cm<sup>−

3</sup>; and

a doped layer doped with dopants of the second type; and

at least one heater integrated in or on the substrate, wherein, when an environmental temperature is below a threshold temperature and in response to a bias being applied thereon, the at least one heater is configured to increase a temperature of the structure to maintain a level of sensitivity of the Ge/Si avalanche photodiode structure, wherein the substrate comprises a Si layer and a buried oxide (BOX) layer adjacent and below the Si layer, and wherein the at least one heater is formed in the Si layer of the substrate.

2. The apparatus of claim 1, wherein the at least one heater comprises a resistive component.

3. The apparatus of claim 1, wherein the resistive component is fabricated by ion implantation, which forms a doped region doped with dopants of the first type.

4. The apparatus of claim 1, wherein dopants of the first type comprise n-type dopants, and wherein dopants of the second type comprise p-type dopants.

5. The apparatus of claim 1, wherein the Ge/Si avalanche photodiode comprises a waveguide structure.

6. The apparatus of claim 1, wherein the Ge/Si avalanche photodiode further comprises one or more electrodes, wherein the at least one heater comprises one or more electrodes different than and separate from the one or more electrodes of the Ge/Si avalanche photodiode.

7. The apparatus of claim 1, wherein the at least one heater comprises metal or TaN.

8. The apparatus of claim 1, further comprising a packaging structure that contains the Ge/Si avalanche photodiode therein, and wherein the packaging structure is of a transistor outline (TO) type or a butterfly type.

9. The apparatus of claim 8, wherein the packaging structure comprises a 6-pin TO-header mounted with the at least one heater integrated in Ge/Si avalanche photodiode.

10. The apparatus of claim 9, wherein an electrode of a resistive component of the at least one heater is connected to one pin of the 6-pin TO header, and wherein another electrode of the resistive component is connected to a ground or a body of the 6-pin TO-header.

11. The apparatus of claim 1, further comprising a temperature control loop configured to be triggered to maintain a temperature of the avalanche photodiode in a range using the at least one heater in response to the environment temperature falling below the threshold temperature.

12. The apparatus of claim 1, further comprising a passivation layer formed over the at least one heater and the Ge/Si avalanche photodiode.

13. The apparatus of claim 12, wherein the passivation layer functions as an anti-reflective layer.