RU1827698C - Charge-coupled device with virtual phase - Google Patents

Abstract

The invention relates to semiconductor ICs, in particular LSIs on charge coupled devices for photosensitive, digital and analog devices. SUMMARY OF THE INVENTION: a charge-coupled device comprises a p-type semiconductor substrate, at the surface of which an n-type layer is formed, which is a channel in which a p-type layer is connected to the substrate, p + are formed in the p-type layer -regions located above the channel. In the n-layer there are four periodically repeating zones with a sequentially increasing concentration of donors n2, n2, n4, n + regions are united at the periphery of the crystal and have a common contact, to which a control pulse arrives. 1 s.p. f-ly, 1 ill.

Description

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The invention relates to semiconductor ICs. in particular LSIs on charge coupled devices for photosensitive, digital and analog devices.

The purpose of the invention is to increase the photosensitivity of the device.

The invention is illustrated in the drawing, which shows a cross section of a charge-coupled device.

The charge coupled device contains a p-type semiconductor substrate 1, at the surface of which a p-type layer is formed, which is a channel in which a p-type 6 layer is connected to the substrate, p-regions are formed in the p-type layer located above the channel in the n-layer there are periodically repeating four zones 2, 3, 4, 5 s in succession

increasing concentration of donors; The n + regions 7 can be combined at the periphery of the crystal and have a common contact to which a control pulse arrives.

The device operates as follows.

In the initial state, due to dynamic timing, all zones of the p-type channel are completely depleted. Narrow p-type gaps located between the n + -regions 7 and the zones of channel 2, 3 are depleted. At the lower level of the clock pulse, the maximum potential in each CCD element, including four zones, is located in zone 5, which has the maximum donor concentration . When applying a high level of clock pulse UV, it enters the n + -region 7 and through a narrow floor

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VI about

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By the depletion of the p-layer, the electric field penetrates into the zones of channel 2, 3, and the potential increases there. The maximum potential in the depth of region 2 becomes higher than the potential of the zn region of the previous CCD element. the potential barrier is removed and the charge packet of the previous CCD element is transmitted to the p-region 3 of this element having the greatest potential. The charge packet of this element n at the same time flows from the gm region 5 to the P2 region of the next element. After the end of the pulse, the level decreases to Kem and the charge from the P2 region 3 flows into the gm region 5.

The proposed CCD is manufactured as follows.

The substrate is KDV-40 silicon with a concentration in NAI 3.5 of 10 cm. An n-channel with an As NA2 concentration of 4.5 1016 is formed in it (such a concentration of donors in the final structure will be only in n-aeon 2). A sequential increase in donor concentrations in zones 3, L, 5 is achieved by ion doping of As with an energy of 1000 keV and a dose, respectively: in zone 3 — dose Dz 0.065 μC / cm2, in zone A — D4 0.1 μC / cm2, in zone 5 - DB 0.15 μC / cm2. Then, temperature distillation was carried out for 350 minutes at T 1000 ° C. Next, a p-type 6 epitaxial layer doped with B. with a NAG of 10 cm 1 μm thick is grown and ion doping of As is carried out with a dose of D7 of 3 μC / cm2 and an energy of 90 keV, followed by thermal distillation for 43 minutes. at 1000 ° C. As a result, the thickness of the narrow pth layer between the n + region 7 and the zones of channel 2, 3 is 0.15 μm, which is less

spatial charge regions from two pn junctions.

This process provides the formation of a structure having high photosensitivity, the charging capacitance of Ohm is 2 pK / μm2 for LiF 20 V, UCM is Oh V.

Using the proposed design allows to increase the photosensitivity of the CCD by eliminating areas

closed by electrodes.

Claims (2)

Claims 1, Virtual phase-coupled device, comprising a p-type semiconductor substrate on which a p-type channel layer is formed, comprising periodically repeating four zones with a successively increasing concentration of donors, over which p- type of conductivity, and the working surface of the device is covered with a thin oxide film, characterized in that, in order to increase the photosensitivity of the device, in each region of the p-type conductivity is additional o areas of the p type conductivity are formed, with each of them located directly above the first two zones of the channel and from divided from them by a gap in the form of a p-type layer conductivity with a thickness of not more than the sum of two regions of the spatial charge formed by the channel-p-region and p-region regions of the p-type conductivity region. 2. The device according to claim 1, characterized in that, in order to simplify the control of the device, additional areas of the n + type conductivity are closed,