Qinetiq Limited

The Secretary of State for Defence in Her Britannic Majesty's Government

Secretary of the State for Defence in Her Majesty's Government of the

Jean Giess

John B Mullin

Neil Thomson Gordon

Stuart J Irvine

Janet E Hails

Louise Buckle

John W Cairns

David J Hall

Andrew Graham

Graham J Pryce

Colin John Hollier

Andrew J Wright

A method of manufacture of cadmium mercury telluride (CMT) is disclosed. The method involves growing one or more buffer layers on a substrate by molecular beam epitaxy (MBE). Subsequently at least one layer of cadmium mercury telluride, Hg1-xCdxTe where x is between 0 and 1 inclusive, is grown by metal organic vapour phase epitaxy (MOVPE). The use of MBE to grow buffer layers allows a range of substrates to be used for CMT growth. The MBE buffer layers provide the correct orientation for later MOVPE growth of CMT and also prevent chemical contamination of the CMT and attack of the substrate during MOVPE. The method also allows for device processing of the CMT layers to be performed with further MOVPE growth of crystalline CMT layers and/or passivation layers. The invention also relates to new devices formed by the method.

Manufacture of cadmium mercury telluride

This invention relates to the manufacture of Cadmium Mercury Telluride (CMT) on patterned silicon, especially to growth of CMT on silicon substrates bearing integrated circuitry. The method of the invention involves growing CMT in selected growth windows on the silicon substrate by first growing one or more buffer layers by MBE and then growing the CMT by MOVPE. The growth windows may be defined by masking the area outside of the growth windows. Growth within the growth windows is crystalline whereas any growth outside the growth windows is polycrystalline and can be removed by etching. The invention offers a method of growing CMT structures directly on integrated circuits removing the need for hybridisation.

Manufacture of cadmium mercury telluride on patterned silicon

A method of growing an epitaxial crystalline layer on a substrate which comprises the steps of

Method of growing crystalline layers by vapor phase epitaxy

A layer of Cd.sub.x Hg.sub.1-x Te is grown on a substrate by growing layers of HgTe t.sub.1 thick, and CdTe t.sub.2 thick alternately. The thicknesses t.sub.1 and t.sub.2 combined are less than 0.5 .mu.m so that interdiffusion occurs during growth to give a single layer of Cd.sub.x Hg.sub.1-x Te. The HgTe layers are grown by flowing a Te alkyl into a vessel containing the substrate and filled with an Hg atmosphere by an Hg bath. The CdTe layers are grown by flowing of Cd alkyl into the vessel where it combines preferentially with the Te on the substrate. Varying the ratio of t.sub.1 to t.sub.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 to dope the growing layer.

Utilizing interdiffusion of sequentially deposited links of HgTe and CdTe

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Malvern, United Kingdom

Jean Giess