Growth of semiconductors on a shaped semiconductor substrate
AssigneeBritish Telecommunications plc
InventorsAndrew W. Nelson, Leslie D. Westbrook
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Abstract
A gas mixture containing phosphine and R.sub.1 R.sub.2 R.sub.3 In X R.sub.4 R.sub.5 R.sub.6 or R.sub.1 R.sub.2 In X R.sub.4 R.sub.5 where the Rs are alkyl groups is passed over a semiconductor substrate comprising indium and phosphorus so as to deposit a semiconductor material comprising indium and phosphorus, and the exposure of the substrate to phosphine is controlled to avoid or reduce transport of the substrate material. Thus, for example, indium phosphide may be grown onto corrugations in gallium indium arsenide phosphide, the corrugations being non-deformed during this growth. Such a growth step may be used in the production of distributed feedback semiconductor lasers operating near 1.55 .mu.m.
Claims50
A method of depositing a further semiconductor layer onto a shaped surface of a different semiconductor substrate, said shaped surface including a diffraction grating, wherein both substrate and grown material comprise indium and phosphorus, in which method the same further layer is grown from a gas mixture containing a phosphorous-compound and an organo-indium compound capable of reaction to grow said further layer by MOCVD, wherein initiation comprises heating the substrate from a temperature below the temperature at which substantial transport of the substrate occurs to the reaction temperature at which deposition growth of the substrate occurs, said growth being initiated less than 1 minute after the transport temperature is first reached.
A method of depositing a further semiconductor layer onto a shaped surface of a different semiconductor substrate, said shaped surface including a diffraction grating, wherein both substrate and grown material comprise indium and phosphorus, in which method the said further layer is grown from a gas mixture containing a phosphorus compound and an organo-indium compound capable of reaction to grow said further layer by MOCVD, wherein initiation comprises:
- (a) heating the substrate from a temperature below 500.degree. C. to a reaction temperature above 575.degree. C.;
- (b) reaching said reaction temperature less than one minute after 500.degree. C. is first reached;
- (c) adding the organometallic reagent before said reaction temperature is reached;
- and
- (d) adding the phosphine not later than the organometallic reagent.
A method of depositing a further semiconductor layer onto a shaped surface of a different semiconductor substrate, said shaped surface including a diffraction grating, wherein both substrate and grown material comprises indium and phosphorus, in which method the said further layer is grown from a gas mixture containing a phosphorus compound and an organo-indium compound capable of reaction to grow said further layer by MOCVD, wherein initiation comprises:
- (a) heating the substrate from a temperature below 200.degree. C. to a reaction temperature above 575.degree. C.;
- (b) reaching said reaction temperature less than one minute after 500.degree. C. is first reached;
- (c) adding the organo-indium compound after 500.degree. C. has been reached and before said reaction temperature is reached;
- and
- (d) adding the phosphorus compound not later than the organo-indium compound.
A method of depositing a further semiconductor layer onto a shaped surface of a different semiconductor substrate, said shaped surface surface including a diffraction grating, wherein both substrate and grown material comprise indium and phosphorus, in which method the said further layer is grown from a gas mixture containing a phosphorus compound and an organ-indium compound capable of reaction to grow said further layer by MOCVD, wherein initiation comprises:
- (a) heating the substrate from a temperature below 500.degree. C. to a reaction temperature in the range of 600.degree. C. to 700.degree. C.;
- (b) reaching 600.degree. C. less than one minute after 500.degree. C. is first reached;
- (c) adding the organo-indium compound not substantially before 500.degree. C. has been reached and not substantially after 600.degree. C. has been reached;
- and
- (d) adding the phosphorus compound not latter than the organo-indium compound.
A method of growing a semiconductor material onto a shaped surface of a different semiconductor substrate, said shaped surface including a diffraction grating, wherein both substrate and growth material comprise indium and phosphorus, in which method the said material is grown from a gas mixture containing phosphine and a compound of the general formula (I), (II) or (III):
- R.sub.1 R.sub.2 R.sub.3 InXR.sub.4 R.sub.5 R.sub.6 (I)
- R.sub.1 R.sub.2 InXR.sub.4 R.sub.5 (II)
- InR.sub.1 R.sub.2 R.sub.3 (III)
- in which R.sub.1 to R.sub.6 are alkyl groups, any two of which may be the same or different, and X is an atom which has an s.sup.2 p.sup.3 outer electron configuration, wherein the exposure of the substrate to phosphine is controlled to less than one minute to avoid or reduce transport of the substrate material aand to substantially avoid deformation of said shaped surface, while exposing the substrate to temperatures at which transport of the substrate would otherwise occur.
A method of growing a semiconductor material onto the shaped corrugated surface of a different semiconductor substrate during the manufacture of a solid state semiconductor device wherein both the shaped corrugated substrate and the material to be grown comprise indium and phosphorus, said method comprising:
- growing the said material by MOCVD from a gas mixture containing phosphine and an organo-indium compound, and
- substantially avoiding prolonged exposure of the shaped substrate to temperatures which are between that required for material transport of said shaped surface in the presence of phosphine and that required to support substantial growth of said material so as to substantially reduce transport of the substrate material and thereby substantially avoid deformation of said shaped corrugated surface within the device, said exposure being limited to less than one minute.
A method of depositing a further semiconductor layer onto the shaped surface of another semiconductor substrate wherein both substrate and grown material comprises indium and phosphorus, in which method the further layer is grown by MOCVD from a gas mixture containing a phosphorus compound and an organo-indium compound, wherein initiation of a MOCVD growth process comprises heating the substrate from a temperature below the temperature required for material transport of said shaped surface in the presence of phosphine to the temperature required to support substantial growth of said material, said growth being initiated less than one minute after the transport temperature is first reached.
A method of growing by MOCVD a layer of phosphorus containing semiconductor material onto the shaped surface of another phosphorus-containing semiconductor substrate without substantial deformation of the shaped surface, said method comprising the steps of:
- heating said semiconductor substrate form a first temperature below that at which material transport of said shaped surface occurs to a second temperature at which MOCVD growth can occur;
- maintaining said substrate approximately at said second temperature for a predetermined growing period;
- and
- passing a metal-organic vapor containing a Group III metal and a phosphorous-containing vapor onto said shaped surface so as to achieve MOCVD growth during said predetermined growing period;
- said heating step being substantially completed and said passing step being started within a time period no greater than approximately one minute.
Dependencies are inferred from the claim text.