OxyNitride Characterization

 

This characterization focused on varying the percent of NO2. All other parameters were maintained constant.

This is the recipe:

Gas1 (NH3): 2.5%
Gas2 (SiH4) : 95%
Gas3 (NO2) : 2.5-25%
Pressure : 900 mTorr
Power : 100 W
Temp : 250 deg

Note: This recipe is no longer valid due to MFC changes. Visit the PECVD Deposition page for details.

 

 

By varying the amount of NO2(Nitrous Oxide) we can change the index of refraction. The effects of the condition of the chamber on the index of refraction of the OxyNitride are unknown. Future characterization would be necessary to determine that.

 

 

The deposition rate increases as NO2 increases.

The index of refraction and deposition thickness were found using the ellipsometer.

Summary of Data:













Wafer Gas1 %NH3 Gas2 %SiH4 Gas3 %NO2 Time (min) p1 a1 p2 a2 δ Φ Thickness Index of Ref.
1 2.5 95 5 10 103.3 35.3 193.2 146.3 63.5 34.4999 725.06 1.7532
2 2.5 95 10 10 116.1 64.6 210 115.9 33.9 64.34999 1086.46 1.6572
3 2.5 95 10 5 95.1 28.1 185.3 152.6 79.5999 27.74999 598.87 1.6238
4 2.5 95 2.5 5 81.8 17 171.88 163.4 106.3999 16.8 282.14 1.7889
5 2.5 95 5 5 86.4 19.8 176.4 161.8 97.2 18.999 344.81 1.7854
6 2.5 95 15 5 98.9 35.4 187.9 143.1 73.2 35.149999 796.99 1.5748
7 2.5 95 20 5 96 31 186.4 144.6 77.6 33.1999 780.8 1.5197
8 2.5 95 25 5 95.3 37.4 185.4 143.2 79.3 37.1 916.52 1.4608
9 2.5 95 7.5 5 90.8 23 180.1 157.4 89.0999 22.8 455.15 1.6569
10 2.5 95 12.5 5 96.7 31 186.7 149.6 76.6 30.6999 685.39 1.5919

 

Using a trend line we can estimate the recipe for desired indices of refraction:



Desired Index Percent NO2 Dep. Rate Ǻ/Min
1.44 24.8% 194
1.45 24.1% 190
1.46 23.4% 186
1.47 22.8% 182
1.48 22.1% 178
1.49 21.4% 174
1.5 20.7% 171
1.51 20.0% 167
1.52 19.4% 163
1.53 18.7% 159
1.54 18.0% 155
1.55 17.3% 151
1.56 16.6% 147
1.57 16.0% 143
1.58 15.3% 139
1.59 14.6% 135
1.6 13.9% 131
1.61 13.2% 128
1.62 12.6% 124
1.63 11.9% 120
1.64 11.2% 116
1.65 10.5% 112
1.66 9.8% 108
1.67 9.2% 104
1.68 8.5% 100
1.69 7.8% 96
1.7 7.1% 92
1.71 6.4% 88
1.72 5.8% 85
1.73 5.1% 81
1.74 4.4% 77
1.75 3.7% 73
1.76 3.0% 69