EP0135344A1
Expired / Lapsed
EP
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Manufacture of cadmium mercury telluride
Assignee: Qinetiq Ltd
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Filing: 1984-08-08
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Granted: —
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Expires: 2004-08-08
Abstract
Abstract A layer (37) of Cd x Hg 1-x Te is grown on a substrate (20) by growing layers of HgTe (35) t, thick and CdTe (36) t 2 thick alternately. The thicknesses t, and t 2 combined are less than 0.5 µm so that interdiffusion occurs during growth to give a single layer (37) of Cd x Hg 1-x Te. The HgTe layers (35) are grown by flowing a Te alkyl (7) into a vessel (16) containing the substrate (20) and filled with an Hg atmosphere by a Hg bath (19). The CdTe layers (36) are grown by flowing a Cd alkyl (6) into the vessel (16) where it combines preferentially with the Te on the substrate (20). Varying the ratio of t, to t 2 varies the value of x. Dopants such as alkyls or hydrides of Al, Ga, As and P, or Si, Ge, As and P respectively may be introduced (25) to dope the growing layer.
Inventors
- 👤 Stuart James Curzon Irvine
- 👤 John Brian Mullin
- 👤 Jean Giess
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 02:13
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/455; C23C16/45561; C23C16/22; C23C16/30; C23C16/305; C23C16/306; H; H10; H10D; H10D62/00; H10D62/80; H10D62/86; H10D62/8603; H10F; H10F71/00; H10F71/125; H10F71/1253; H10F77/00; H10F77/10; H10F77/12; H10F77/123; H10F77/1237; H10P; H10P14/00; H10P14/20; H10P14/24; H10P14/29; H10P14/2901; H10P14/2913; H10P14/2917; H10P14/32; H10P14/3202; H10P14/3224; H10P14/3232; H10P14/3242; H10P14/3244; H10P14/3251; H10P14/3252; H10P14/34; H10P14/3402; H10P14/3424; H10P14/3432; H10P14/3438; H10P14/3441; Y; Y10; Y10S; Y10S148/00; Y10S148/063; Y10S148/064; Y10S148/16
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
194 words
A method of growing a layer of the ternary alloy Cd x Hg 1-x Te onto a substrate comprises the steps of providing an atmosphere of mercury vapour at a required temperature and pressure inside a vessel; controlling the temperature of the substrate independently of the vessel temperature; providing separate supplies of a cadmium compound, a tellurium compound, and a dilutant gas into the vessel to grow a layer of HgTe t thick and a layer of CdTe t 2 thick in either order; switching the supply of cadmium compound to the substrate on and off to grow a layer of CdTe and of HgTe, the combined thickness t 1 + t 2 of the two layers being not greater than 0.5 pm thick, the arrangement being such that the Cd compound decomposes preferentially with the Te compound in the region of the substrate to form CdTe as a layer on the substratre, the Te compound combines with the Hg vapour to form a HgTe layer on the substrate, the thickness of both layers allowing diffusion during growth to give a layer of Cd x Hg 1-x Te where 0 < x < 1.
Claim 2
Independent Claim
194 words
A method of growing a layer of the ternary alloy Cd x Hg 1-x Te onto a substrate comprises the steps of providing an atmosphere of mercury vapour at a required temperature and pressure inside a vessel; controlling the temperature of the substrate independently of the vessel temperature; providing separate supplies of a cadmium compound, a tellurium compound, and a dilutant gas into the vessel to grow a layer of HgTe t thick and a layer of CdTe t 2 thick in either order; switching the supply of cadmium compound to the substrate on and off to grow a layer of CdTe and of HgTe, the combined thickness t 1 + t 2 of the two layers being not greater than 0.5 pm thick, the arrangement being such that the Cd compound decomposes preferentially with the Te compound in the region of the substrate to form CdTe as a layer on the substratre, the Te compound combines with the Hg vapour to form a HgTe layer on the substrate, the thickness of both layers allowing diffusion during growth to give a layer of Cd x Hg 1-x Te where 0 < x < 1.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein 0.1 ≼ x ≼ 0.9.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the combined thickness t + t is less than 0.25 pm.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein the temperature of the o substrate is within 400 to 430 C.
Claim 6
Dependent Claim
33 words
The method of claim 1 wherein the ratio of t and t and 1 2 hence the value of x is varied during growth of the Cd x H g 1-x Te layer.
Claim 7
Dependent Claim
49 words
The method of claim 1 and further comprising the steps of stopping the flows of Cd and Te compounds over the substrate, allowing Hg and dilutant gas to flow over the substrate whilst the last grown layer diffuses with the previous layer for a period less than 10 minutes.
Claim 8
Dependent Claim
22 words
The method of claim 1 and further comprising the step of admitting a dopant compound into the vessel and over the substrate.
Claim 9
Dependent Claim
30 words
The method of claim 1 wherein a further layer is grown on the Cd x Hg 1-x Te, said further layer being of CdTe, ZnS, or CdTe Se x 1-x
Claim 10
Dependent Claim
21 words
The method of claim 1 wherein the Cd compound is an alkyl selected from dimethyl cadmium, diethyl cadmium, or dipropyl cadmium.
Claim 11
Dependent Claim
37 words
The method of claim 1 wherein the Te compound is on the alkyl selected from diethyl telluride, dimethyl telluride, dipropyl telluride, or dibutyl telluride, etc., or equivalent hydrogen substituted tellurium alkyls, or equivalent hydrogen substituted tellurium alkyls.
Claim 12
Dependent Claim
69 words
The method of claim 1 wherein the dopant compound is an alkyl selected from the group (CH ) Al, (CH ) Ga, (CH 3 ) 3 As, (CH 3 ) 3 P, (C 2 H 5 ) 3 Al, (C 2 H 5 ) 3 Ga, (C H 5 ) P or a hydride selected from the group SiH , GeH 4 , AsH 3 , PH 3 .
Claim 13
Dependent Claim
23 words
The method of claim 1 wherein the substrate is CdTe, Si, GaAs, NgAl 2 O 4 , or Al 2 O 3 .
Claim 14
Dependent Claim
25 words
The method of claim 1 wherein the supply of cadmium compound to the vessel is switched on and off whilst growing CdTe and HgTe layers.
Claim 15
Dependent Claim
15 words
The method of claim 1 substantially as hereinbefore described with reference to the accompanying drawings.
Claim 16
Dependent Claim
18 words
A substrate having a layer of Cd x Hg 1-x Te grown by the method of claim 1.
Claim 17
Dependent Claim
14 words
The substrate of claim 15 wherein the value of x varies within the layer.
Claim 18
Dependent Claim
22 words
The substrate of claim 15 having a passivating layer of CdTe grown on top of the Cd x Hg 1-x Te layer.
References Cited (Backward Citations)
GB2078695A
Cited
EP0068652A2
Cited
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