Geiger-mode focal plane array with monolithically integrated resistors
A GmAPD FPA having increased tolerance optical overstress includes a limit resistor that is monolithically integrated into each pixel in the FPA, and which limits the magnitude of the current entering the read out integrated circuit.
1. A method of controlling a Geiger-mode avalanche photodiode (GmAPD) focal plane array (FPA), the method comprising:
increasing, within each pixel of the GmAPD FPA, a series resistance of an electrical connection between the GmAPD and a unit cell of a read out integrated circuit (ROIC unit cell), the ROIC unit cell having an active quenching circuit.
2. The method of claim 1 , wherein the electrical connection is between an electrical contact of the GmAPD and an input of a sense transistor in the active quenching circuit within the ROIC unit cell.
3. The method of claim 1 , wherein increasing the series resistance includes increasing the series resistance by an amount in a range of about 1 kOhm to about 100 kOhms.
4. The method of claim 1 , wherein increasing the series resistance comprises using a thin-film resistor.
5. The method of claim 4 , wherein increasing the series resistance comprises monolithically integrating the thin-film resistor into each pixel of the GmAPD FPA.
6. The method of claim 5 , wherein increasing the series resistance comprises monolithically integrating the thin-film resistor into a GmAPD of each pixel of the GmAPD FPA.
7. The method of claim 5 , wherein increasing the series resistance comprises monolithically integrating the thin-film resistor into the ROIC unit cell in each pixel of the GmAPD FPA.
8. The method of claim 4 , wherein the thin-film resistor has a serpentine shape.
9. The method of claim 1 , wherein the active quenching circuit comprises an arm transistor, a disarm transistor, and a sense transistor.
10. The method of claim 1 , wherein increasing the series resistance comprises monolithically integrating a first thin-film resistor into a GmAPD of some pixels of the GmAPD FPA and integrating a second thin-film resistor into the ROIC unit cell of said some pixels of the GmAPD FPA.
11. A method of controlling a Geiger-mode avalanche photodiode (GmAPD) focal plane array (FPA), the method comprising:
monolithically integrating, into each pixel of the GmAPD FPA, a limit resistor,
wherein the limit resistor is electrically coupled in series to an electrical contact of the GmAPD and to an active quenching circuit within a unit cell of a read out integrated circuit (ROIC unit cell).
12. The method of claim 11 , wherein the electrical coupling to the active quenching circuit is to an input of a sense transistor in said active quenching circuit.
13. The method of claim 11 , wherein the limit resistor increases the series resistance of the electrical coupling by an amount in the range of about 1 kOhm to about 100 kOhms.
14. The method of claim 11 , wherein monolithically integrating the limit resistor into each pixel of the GmAPD FPA comprises monolithically integrating the limit resistor into a GmAPD in each pixel of the GmAPD FPA.
15. The method of claim 11 , wherein monolithically integrating the limit resistor into each pixel of the GmAPD FPA comprises monolithically integrating the limit resistor into a ROIC unit cell in each pixel of the GmAPD FPA.
16. The method of claim 11 , wherein monolithically integrating the limit resistor into each pixel of the GmAPD FPA comprises monolithically integrating a first limit resistor into a GmAPD of some pixels of the GmAPD FPA and integrating a second thin-film resistor into the ROIC unit cell of said some pixels of the GmAPD FPA.
17. The method of claim 11 , wherein the limit resistor is a thin-film resistor.
18. The method of claim 17 , wherein the limit resistor has a serpentine shape.