Appendix A - SEM and Raman Data

 

“amere et sapere vix deo conceditur”

 

Appendix A: SEM Images and Raman Spectra from MWCVD Diamond Films

 

This appendix presents data pertinent to the results chapters of this thesis.  Thus the data in this chapter does not present a coherent ‘story’ on it’s own, but should be referred to by the reader when reading the results chapters of this thesis.

 

A.1      Effect of Deposition Time

 

Conditions kept constant for the growth runs where the effect of deposition time on diamond film thickness and morphology was studied (Section 4.2.1) are given in Table A.1.  SEM micrograph images of films grown for increasing lengths of time are shown in Figs. A.1-A.4

 

Constant Conditions

Old Substrate Holder (OSH)

Microwave power (W)

1000

Substrate temperature (K)

1073

Pressure (Torr)

30

Input CH4 mole fraction (%)

0.72

 

Table A.1  Constant conditions used for MWCVD diamond film growth, whilst increasing the deposition time.  The substrate temperature given here is that measured by the thermocouple in the substrate holder.


 

Figure A.1a & b:  1.5 hours growth (Sample MW88).

 

Figure A.2  6.0 hours growth (MW88).            Figure A.3  13.0 hours growth (MW88).

 

 Figure A.4  18.7 hours growth (MW88).

 

Figures A.1-A.4:  SEM images of CVD diamond films grown under the conditions given in Table A.1.  A representative Raman spectrum of the film in Fig. A.1a is shown in Fig. A.1b.

 

A.2      Effect of CH4 mole fraction in H2 feed

 

Constant Conditions

Old Substrate Holder

(OSH)

New Substrate Holder

(NSH)

Microwave power (W)

1000

1000

Substrate temperature (K)

1073

973

Pressure (Torr)

30

30

Growth Time (hours)

6.0

6.0

 

Table A.2 Constant conditions used for MWCVD diamond film growth whilst varying the mole fraction of CH4 in the H2 feed gas.

 


Figure A.5  0.36% input CH4 mole fraction (OSH, MW44).

Figure A.6  0.54% input CH4 mole fraction (OSH, MW59).



 


Figure A.7  0.72% input CH4 mole fraction (OSH, MW32).

Figure A.8  1.08% input CH4 mole fraction (OSH, MW 47).


 


Figure A.9 1.44% input CH4 mole fraction (OSH, MW46).

Figure A.10 1.80% input CH4 mole fraction (OSH, MW48).


 

Note to Figs. A.5-A.10:  Raman spectra for CVD diamond films with increasing input CH4 were presented in chapter 4 (Fig. 4.3).


 

Figure A.11a & b:  0.36% input CH4 mole fraction (NSH, MW112)

 

Figure A.12a & b:  0.72% input CH4 mole fraction (NSH, MW97)

 

Figure A.13a & b:  1.08% input CH4 mole fraction (NSH, MW102)


 

 

Figure A.14a & b:  1.44% input CH4 mole fraction (NSH, MW100)

 

Figure A.15a & b:  2.16% input CH4 mole fraction (NSH, MW103)


 

A.3      Variation of applied Microwave Power

 

Constant Conditions

Old Substrate Holder (OSH)

New Substrate Holder (NSH)

Input CH4 mole fraction (%)

0.72

0.72

Substrate temperature (K)

1073

973

Pressure (Torr)

30

30

Growth Time (hours)

6.0

6.0

 

Table A.3 Constant conditions used for MWCVD diamond film growth whilst varying the microwave power level used to sustain the plasma.

 

Figure A.16a & b:  800 W (OSH, MW41).

 


 

Figure A.17a & b:  900 W (OSH, MW55).

 

Figure A.18a & b:  1100 W (OSH, MW56).

 

Figure A.19:  1200 W (OSH, MW83).

 


 

Figure A.20a & b:  600 W (NSH, MW111).

 

Figure A.21a & b:  800 W (NSH, MW110).

 

Figure A.22a & b:  900 W (NSH, MW113).

 


 

Figure A.23a & b:  1100 W (NSH, MW115).

 

Figure A.24a & b:  1200 W (NSH, MW109).

 


 

A.4      Effect of CVD Reactor Pressure

 

Constant Conditions

Old Substrate Holder (OSH)

New Substrate Holder (NSH)

Input CH4 mole fraction (%)

0.72

0.72

Substrate temperature (K)

1073

973

Microwave Power (W)

1000

1000

Growth Time (hours)

6.0

6.0

 

Table A.4 Constant conditions used for MWCVD diamond film growth whilst varying the reactor pressure.

 

Figure A.25a & b:  20 Torr (OSH, MW33).

 


 

Figure A.26a & b:  25 Torr (OSH, MW58).

 

Figure A.27a & b:  35 Torr (OSH, MW60).

 

Figure A.28a & b:  40 Torr (OSH, MW34).

 


 

Figure A.29a & b:  50 Torr (OSH, MW37).

 

Figure A.30a & b:  20 Torr (NSH, MW106).

 

Figure A.31a & b:  40 Torr (NSH, MW105).

 


 

Figure A.32a & b:  55 Torr (NSH, MW104).

 

A.5      Effect of substrate holder vertical position

Figure A.33  SEM image of CVD diamond film grown using a pressure of 30 Torr, 700°C substrate temperature, 1000 W microwave power, 0.72% CH4/H2. 6 hours growth, using the new substrate holder positioned at Z = 23 mm (Sample MW120).

 


 

A.5      Effect of Substrate Temperature

 

Constant Conditions

Both Substrate Holders

Input [CH4] (%)

0.72

Pressure (Torr)

30

Microwave Power (W)

1000

Growth Time (hours)

6.0

 

Table A.5  Constant conditions used for growth of CVD diamond films whilst examining the effect of substrate temperature.

 

Figure A.34a & b:  700°C (OSH, MW53).

 


 

Figure A.35a & b:  750°C (OSH, MW35).

 

Figure A.36a & b:  775°C (OSH, MW57).

 

Figure A.37a & b:  850°C (OSH, MW36).

 


 

Figure A.38:  383°C (NSH, MW125).

 

Figure A.39a & b:  550°C (NSH, MW107).

 

Figure A.40a & b:  600°C (NSH, MW101).

 


 

Figure A.41:  625°C (NSH, MW114).

 

Figure A.42a & b:  650°C (NSH, MW98).

 

Figure A.43a & b:  750°C (NSH, MW99).