Texas Instruments, Incorporated

S. N. Rea, Texas Instruments Incorporated Monthly Technical Progress Report, No. 03-76-31, ERDA/JPL 954475-76-11, Texas Instmments, Dallas, May 1976. 

Givens, L. Texas Instruments Incorporated, private communication. Froman-Bentchkowsky, D. Lenzlinger, M. J. Appl. Phys. 1969, 3307. 

Baker, C. Texas Instruments Incorporated, private communication. 

Texas Instruments Incorporated, P.O. Box 5936, Dallas, Tex. 75222. fBrown University, Providence, R.I. 02912 tBrookhaven National Laboratories, Upton, N.Y. 11973. 

A charge coupled device infrared imager having an HgCdTe substrate is disclosed in US-A-3806729 (Texas Instruments Incorporated, USA, 23.04.74). 

A uniphase, buried channel charge transfer device is disclosed in US-A-4229752 (Texas Instruments Incorporated, USA, 21.10.80) wherein a portion of each cell includes an inversion layer, or "virtual electrode" at the semiconductor surface, shielding that region from any gate-induced change in potential. 

A problem with imagers adopting the TDI method is that the charge packets in the parallel shift register potential wells increase in size from the first to the last stages and overflow after saturation. This problem is addressed in EP-A-0066020 (Texas Instruments Incorporated, USA, 08.12.82). 

A two colour infrared focal plane array with the two colours detectors interleaved and with a single set of read-out lines for both colours is presented in US-A-4956686 (Texas Instruments Incorporated, USA, 11.09.90). 

The imager of US-A-5144138 (Texas Instruments Incorporated, USA, 01.09.92) comprises photocapacitors which include a heterojunction. The structure has the advantages of a large potential well capacity, small amount of dark current and detection of two colours. Other features of this document are presented in chapter 2.S. 

An interconnection pattern is used instead of wire interconnects in US-A-3965568 (Texas Instruments Incorporated, USA, 29.06.76) to increase the practical limit of the number of elements in an array. 

A thin metal layer of nickel is often used as a transparent gate of MIS photo-detectors in the infrared range. To reduce the absorbtion of photons in the gate, it is made as thin as possible. However, when the layer thickness is less than 6 nm the device yields drop off dramatically. A gate of nickel having a thickness of 6 nm absorbs from about 30 to 40 percent of the radiation. A solution to this problem is found in US-A-4654686 (Texas Instruments Incorporated, USA, 31.03.87) where a portion of the metal layer forming the gate is eliminated. 

At the time US-A-3808435 (Texas Instruments Incorporated, USA, 30.04.74) was filed, a conventional infrared detector system had an array of infrared detectors and each detector had an amplifier for amplifying its output. The amplified output was connected to a multiplexer... 

In US-A-3980915 (Texas Instruments Incorporated, USA, 14 09.76) Schottky diodes constitute the detector elements of an imager. 

An imager having HgCdTe detectors made of different compositions to be responsive to two different infrared frequency windows, and having the detectors formed in the same focal plane is presented in US-A-4620209 (Texas Instruments Incorporated, USA, 28.10.86). 

A two colour infrared detector is described in US-A-5300777 (Texas Instruments Incorporated, USA, 05.04.94) which for each detector element comprises a heterojunction diode and a metal-insulator-semiconductor device. 

A similar imager is presented in US-A-4761681 (Texas Instruments Incorporated, USA, 21.04.87) and US-A-4660066 (Texas Instruments Incorporated, USA, 02.08.88) where a silicon chip has mesas covered with metal contacts to which a detector chip is connected by a flip-chip technique. The read-out circuit is either formed on the mesa side of the silicon chip or on the opposite side. In the latter case, connections are made via conductive elements extending through the silicon substrate. These documents do not specify the material of the detector chip. 

In US-A-4720738 (Texas Instruments Incorporated, USA, 19.01.88) an HgCdTe layer is attached to a read-out substrate. Detector elements are connected to aluminium buses which are connected to bonding pads on the substrate via conductors that occupy holes through the HgCdTe layer. 

An imager connecting pn-junction detectors or MIS detectors to connection pads of a silicon read-out chip via through holes is presented in EP-A-0137988 (Texas Instruments Incorporated, USA, 24.04.85). The through holes are created by first ion-milling small holes and then enlarge the same by spray etching. 

The storage gate of EP-A-013 7988, presented above, is formed of nickel or chromium. There is a tradeoff between transmittance and electrical conductivity of the gate. This problem is further analysed in EP-A-0416299 (Texas Instruments Incorporated, USA, 13.03.91). It is proposed to use bismuth (Bi), antimony (Sb) or titanium oxynitride (TiNxOy). 

A process for forming a ZnS insulative layer on an HgCdTe material characterized by the absence of an intermediate native oxide layer is taught in EP-A-0366886 (Texas Instruments Incorporated, USA 09.05.90). 

A problem encountered when aluminium is used as gate metal for a MIS structure is the significant etching of the aluminium by the bromine solution which is used to form vias or contacts in overlaying ZnS insulator films. To solve this problem, it is proposed in EP-A-0407062 (Texas Instruments Incorporated, USA, 09.01.91) to use refractory metals as the metallization layers of an infrared detector. 

In US-A-5318666 (Texas Instruments Incorporated, USA, 07.06.94) photodiodes and vias are formed simultaneously by employing a dry reactive etching process. Portions of an HgCdTe body adjacent to the vias are thereby type converted. 

A metal interconnect fabrication process is disclosed in US-A-5384267 (Texas Instruments Incorporated, USA, 24.01.95). A metal layer and a photoresist layer are formed on an array of HgCdTe detectors. The photoresist layer is patterned to form a positive mask and the metal interconnect is formed by using a dry etching technique. 

Applicant Texas Instruments Incorporated, Priority US830528206 31.08.83 ... 

---