Source: https://patents.justia.com/patent/7397101
Timestamp: 2020-06-02 11:25:05
Document Index: 796798841

Matched Legal Cases: ['§ 119', 'Application No. 60', '§ 119', 'Application No. 60', '§ 119', 'Application No. 60']

US Patent for Germanium silicon heterostructure photodetectors Patent (Patent # 7,397,101 issued July 8, 2008) - Justia Patents Search
Justia Patents Pin Detector, Including Combinations With Non-light Responsive Active DevicesUS Patent for Germanium silicon heterostructure photodetectors Patent (Patent # 7,397,101)
Jul 7, 2005 - Luxtera, Inc.
This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60/586,205 filed on Jul. 8, 2004, entitled “SAM-APD GeSi Waveguide Photodetector,” which is incorporated by reference herein in its entirety. This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60/586,161 filed on Jul. 8, 2004, entitled “Out-diffusion Contacted GeSi Waveguide Photodetector,” which is incorporated by reference herein in its entirety. This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60/589,298 filed on Jul. 20, 2004, entitled “Germanium Integration,” which is incorporated by reference herein in its entirety.
FIGS. 3a and b illustrate overhead views of examples of a detector according to the current invention.
FIG. 7a illustrates an example of an integrated avalanche photodetector according to the current invention.
FIG. 7b illustrates an overhead view of an example of an integrated avalanche photodetector according to the current invention.
FIG. 8a illustrates an example of an integrated avalanche photodetector according to the current invention.
FIG. 8b illustrates an overhead view of an example of an integrated avalanche photodetector according to the current invention.
FIGS. 9a, 9b, 10a and 10b illustrate examples of other configurations for avalanche photodetectors according to the current invention.
According to the current invention, in order to enable coupling to the germanium p-i-n through the silicon contacts, the p-type doped silicon region and the p-type doped germanium region must be in electrical contact; similarly, the n-type doped silicon region and the n-type doped germanium region must be in electrical contact. In some examples according to the current invention, the silicon p-i-n and the germanium p-i-n are of similar size and area and are substantially aligned. However, in other examples according to the current invention, the silicon p-i-n and the germanium p-i-n may be somewhat offset. Furthermore, in some cases, the silicon p-i-n and germanium p-i-n may have different shapes and/or dimensions. FIG. 3a illustrates an overhead view of an example of a detector according to the current invention. In this example, the silicon p-i-n is formed by silicon p-type doped region 265, silicon n-type doped region 275 and the portion of intrinsic silicon region 270 between regions 265 and 275; the smaller germanium p-i-n is formed by p-type doped germanium region 280, intrinsic germanium region 285 and n-type doped germanium region 290. In this example, the silicon p-i-n and the germanium p-i-n have different sizes but similar shapes. In other examples according to the current invention, the silicon p-i-n and the germanium p-i-n may or may not have the same basic shape. For example, FIG. 3b illustrates an overhead view of an example of a detector according to the current invention; in this example, the germanium p-i-n and the silicon p-i-n are not the same shape.
FIGS. 7a and 8a illustrate examples of integrated avalanche photodetectors 561 and 601 according to the current invention. According to the current invention, an integrated avalanche photodetector may be formed from a germanium silicon heterostructure. A germanium absorption region (such as 575 or 620) for absorbing photons is in contact with a silicon avalanche region (such as 580 and 625). Cathode contacts (such as 595 and 640) and anode contacts (such as 590 and 635) enable the application of a bias voltage across the heterostructure.
According to the current invention, an integrated avalanche photodetector comprises a germanium silicon heterostructure disposed on a substrate. In the examples illustrated in FIGS. 7a and 8a, the substrate is a silicon substrate. However, in other examples according to the current invention, other substrates may be used such as, but not limited to, a silicon-on-insulator (SOI) substrate or a silicon-on-sapphire (SOS) substrate.
In some examples of an integrated avalanche photodetector according to the current invention, a cathode contact 595 may be established to n-type doped silicon material 585 and an anode contact 590 may be established to p-type doped germanium material 570 as illustrated in FIG. 7a. However, according to another example of the current invention, both the anode contact and the cathode contact may be established to silicon material. In some cases, using only silicon contacts may make processing and/or CMOS process integration simpler. For example, an anode contact 635 may be established to silicon material such as p-type doped silicon region 610 in FIG. 8a. In this example, electrical contact is established from contact 635, through an alloyed/doped contact region 636, though p-type doped silicon region 610, through p-type doped germanium region 615 to the intrinsic germanium region 620. A low field collection region may be established in the intrinsic germanium region 620 and a high field avalanche region may be established in the intrinsic silicon region 625 when a reverse bias voltage is applied across the anode 635 and the cathode 640.
According the current invention, a variety of configurations are possible. FIGS. 9a, 9b, 10a and 10b illustrate examples of other configurations for avalanche photodetectors according to the current invention.
In some cases, an integrated avalanche photodetector according to the current invention may be integrated with an on-chip waveguide such as, but not limited to, an integrated silicon or silicon and germanium heterostructure optical waveguide. FIGS. 7b and 8b illustrate overhead views of two examples of integrated avalanche photodetectors according to the current invention. In some cases, some or all of the silicon and/or germanium associated with an integrated waveguide may be deposited, grown, patterned and/or doped concurrently in the same processing step(s) as some or all of the silicon and/or germanium which forms the detector's silicon avalanche region and/or the germanium absorption region. For example, in FIGS. 8a and 8b, integrated silicon waveguides 571 and 621 are optically coupled to and monolithically integrated with a waveguide according to the current invention.
a horizontal silicon pin (positive-intrinsic-negative) diode disposed on a substrate comprising: a first positive region comprising p-type doped silicon; a first intrinsic region comprising silicon; and, a first negative region comprising n-type doped silicon;
a horizontal germanium pin diode disposed on top of the horizontal silicon pin diode comprising: a second positive region comprising p-type doped germanium substantially aligned with the first positive region; a second intrinsic region comprising germanium substantially aligned with the first intrinsic region; and, a second negative region comprising n-type doped germanium substantially aligned with the first negative region;
Gianlorenzo Masini, et al. “High-Performance p-i-n Ge on Si Photodetectors for the Near Infrared: From Model to Demonstration”, Jun. 2001, 5 pages, vol. 48, No. 6.
Patent number: 7397101
Inventors: Gianlorenzo Masini (Carlsbad, CA), Lawrence C. Gunn, III (Encinitas, CA), Giovanni Capellini (Rome)
Assistant Examiner: Jay Kim
Application Number: 11/177,132
Current U.S. Class: Pin Detector, Including Combinations With Non-light Responsive Active Devices (257/458); 257/E31.61; With High Resistivity (e.g., "intrinsic") Layer Between P And N Layers (e.g., Pin Diode) (257/656); Light Responsive Structure (257/184); Containing Germanium, Ge (257/616)